CN114559220A

CN114559220A - Machining tool and machining method for thin-block cam with stepped hole

Info

Publication number: CN114559220A
Application number: CN202210225983.3A
Authority: CN
Inventors: 周改梅; 胡彩侠; 张维; 朱海浪; 李蕊; 师少青; 霍德怀
Original assignee: Shaanxi Weihe Tools Co ltd
Current assignee: Shaanxi Weihe Tools Co ltd
Priority date: 2022-03-09
Filing date: 2022-03-09
Publication date: 2022-05-31

Abstract

The machining tool and the machining method of the thin-block cam with the stepped hole are provided, wherein a small-diameter through hole of the cam is machined, the cam is clamped on a nut mandrel, the outer contour line of the cam is machined, the cam is removed, the cam is clamped on a gland mandrel, and a large-diameter through hole of the cam is machined. The tool is simple in structure, simple in number of components, simple to assemble and reliable in positioning, and ensures the machining symmetry degree of the cam and the machining precision of the stepped hole of the cam; the high-precision machining requirement of a thin-block cam with a stepped hole and an axial length of less than 10mm is fully met; the harmonic waves such as the symmetry degree of the cam, the straightness and the parallelism of the bus, the tolerance grade of the stepped hole and the form and position tolerance circular runout can meet the requirements, and the method is suitable for popularization.

Description

Machining tool and machining method for thin-block cam with stepped hole

Technical Field

The invention belongs to the technical field of tools for processing workpieces on operation transportation machine tools, and particularly relates to a processing tool and a processing method for a thin-block cam with a stepped hole.

Background

At present, the main component of the generator in the harmonic gear transmission is a cam, and the profile of the cam has an elliptical form and a cosine form. According to experience, when the position length of the installation mandrel is smaller than 10mm, the adopted cam profile machining method is milling machining performed by a machining center. However, with the research on harmonic transmission technology, it is found that the symmetry of the cam greatly affects the harmonic transmission precision, and the symmetry of the cam milled in the machining center is about 0.03 mm: referring to the cam configuration shown in fig. 1: the symmetry of the sizes C and D of the long and short axes of the cam is required to be 0.005mm, the straightness and the parallelism of the bus are required to be 0.005mm, and the requirements cannot be met by milling by a machining center; therefore, it is difficult to meet the higher and higher precision requirements of harmonic drive. Furthermore, when the cam grinding is adopted for processing, the stepped hole is formed

And

the axial lengths of the connecting rods are respectively L2 being 4mm, L1 being 3mm and far less than 10 mm; therefore, the cam grinding cannot be performed with reference to any one hole, and the hole is formed

The required dimensional tolerance is H6 tolerance grade, the form and position tolerance is that the circular runout is less than or equal to 0.01mm, and the precision is higher. Therefore, it is necessary to develop a suitable machining process for such parts, and to improve the machining of the thin block type cam with the stepped hole. In view of this, the following technical solutions are proposed.

Disclosure of Invention

The technical problems solved by the invention are as follows: the processing tool and the processing method for the thin block type cam with the stepped hole meet the high-precision processing requirement of the thin block type cam with the stepped hole.

The technical scheme adopted by the invention is as follows: the processing method of the thin block type cam with the stepped hole comprises the following steps:

step S1, machining a small-diameter through hole of the cam: finely turning a small-diameter through hole in the cam stepped hole; and the small-diameter through hole is processed into a through hole concentric with the cam.

Step S2, clamping the cam on the nut mandrel tool: clamping the cam processed according to the step S1 on a nut mandrel tool, and specifically comprises the following steps:

step S201, finding direction: and (5) facing the edge of the cam thin block to the nut mandrel tool.

Step S202, centering: and concentrically sleeving the small-diameter through hole of the cam on a step mandrel I of the nut mandrel tool.

Step S203, assembling: and a gasket and a nut are sleeved on the step mandrel I in sequence.

Step S204, compressing and fixing: an external thread I is formed at the outer side shaft end of the nut screwing step mandrel I; and screwing the nut until the nut and the gasket compress and fix the cam concentrically and axially on the horizontal step positioning surface I of the step mandrel I.

Step S3, processing the outer contour of the cam: two sides of the shaft end of a step mandrel I in the nut mandrel tool are respectively provided with a central hole; the center hole of a nut mandrel tool provided with a clamped cam is clamped with a chuck and a tip of a cam grinding machine tool in a concentric manner; the cam outer profile is then machined using a cam grinder machine.

Step S4, removing the cam: firstly, removing a nut mandrel tool from a cam grinding machine; and then the cam is detached from the nut mandrel tool.

Step S5, clamping the cam on the gland mandrel tool: clamping the cam processed in the step S4 on a gland mandrel tool, and specifically comprises the following steps:

step S501, finding direction: the cam thin piece edge faces the outside.

Step S502, centering: and concentrically sleeving the small-diameter through hole of the cam on a step mandrel II of the gland mandrel tool.

Step S503, assembling: and the internal thread formed by the gland is screwed to be matched with the external thread II formed by the gland mandrel tool in an adaptive manner.

Step S504, compressing and fixing: and screwing the gland until the gland concentrically and axially compresses and fixes the cam on the horizontal step positioning surface II of the step mandrel II.

Step S6, machining the large-diameter through hole of the cam: and (4) passing through the avoidance hole in the center of the gland, and turning the large-diameter through hole of the cam.

In the above technical solution, further: and S6, after the large-diameter through hole of the cam is machined, continuing to clamp the cam by using the gland mandrel tool to machine the inclined hole at the outer shaft end of the large-diameter through hole of the cam.

In the above technical solution, further: the small diameter through hole dimension tolerance level in the step S1 is H6 level.

In the above technical solution, further: and in step 202, the small-diameter through hole is installed with the step mandrel I in an interference fit mode.

In the above technical solution, further: and step S502, the small-diameter through hole and the step mandrel II are installed in a transition fit mode.

In the above technical solution, further: in step S6, a pressing boss is arranged on the inner side edge of the shaft end of the central avoidance hole; the compression boss fits over and avoids the slab edge of the cam to axially compress the cam.

The machining tool for the thin block type cam with the stepped hole comprises a nut mandrel tool and a gland mandrel tool.

The nut mandrel tool consists of a step mandrel I, a gasket and a nut; the step mandrel I is provided with a horizontal step positioning surface I; the step mandrel I is concentrically and horizontally sleeved with a positioning cam through a step positioning surface I; an external thread I is formed at the shaft end of the step mandrel I; the nut is screwed to match the external thread I so as to compress and fix the cam between the gasket and the step mandrel I in a horizontal concentric axial direction.

The gland mandrel tool consists of a step mandrel II and a gland; a central avoidance hole is concentrically formed in the center of the gland; the step mandrel II is provided with a horizontal step positioning surface II; the step mandrel II is concentrically and horizontally sleeved with a positioning cam through a step positioning surface II; the inner side of the gland cover body is provided with internal threads; an external thread II is formed on the outer side of the shaft body of the step mandrel II; the internal thread is screwed to be matched with the external thread II so as to compress and fix the cam between the gland and the step mandrel II in a horizontal concentric axial direction.

In the above technical solution, further: the cam is installed with the step mandrel I in an interference fit manner; the cam is installed with the step mandrel II in a transition fit mode.

In the above technical solution, further: a pressing boss is arranged on the inner side edge of the shaft end of the central avoidance hole; the compression boss fits over and avoids the slab edge of the cam to axially compress the cam.

In the above technical solution, further: the center of the shaft end of the step mandrel I is concentrically provided with a central hole.

Compared with the prior art, the invention has the advantages that:

1. the nut mandrel tool and the gland mandrel tool are simple in structure, simple in component number, simple to assemble and reliable in positioning, and the machining symmetry of the cam is guaranteed while the machining precision of the cam stepped hole is guaranteed.

2. According to the invention, the small-diameter through hole is firstly finely turned, then the cam is assembled on the tool, and the length of the small-diameter through hole effectively increases the matching length of the cam and the step mandrels I and II, so that the grinding precision of the cam is improved.

3. The first shaft end of the step mandrel of the nut mandrel tool is provided with a central hole, and the central hole of the tool is positioned and clamped on a cam grinding machine by using a chuck and a tip, so that the cam, the tool and the grinding cam contour line center of the machine tool are well positioned, and the machining precision is ensured.

4. The step positioning surface I of the step mandrel I is used for positioning the inner side of the end of the cam shaft and is cooperated with the interference fit of the step mandrel I and the small-diameter through hole of the cam, so that the cam cannot be inclined when a machine tool grinds the cam contour line, and the symmetry of the long and short axis sizes of the cam and the straightness of a bus are ensured; meanwhile, the rigidity of the step mandrel I with the step structure is increased, the vibration of the cam during grinding is reduced, and the cam grinding precision is improved.

5. The step mandrel II of the gland mandrel tool is cooperated with the step positioning surface II to concentrically and horizontally compress the fixed cam; the cam is positioned concentrically and accurately; and the pressing boss on the inner side of the pressing cover prevents the pressing from pressing the edge of the cam thin block, so that the cam is prevented from being inclined and deformed in the machining process.

6. The invention meets the high-precision processing requirement of a thin-block cam with an axial length less than 10mm, such as a stepped hole; the harmonic waves such as the symmetry degree of the cam, the straightness and the parallelism of the bus, the tolerance grade of the step hole and the form and position tolerance circular runout can all reach high standard requirements, and the method is suitable for popularization.

Drawings

FIG. 1 is a process diagram of a cam to be machined according to the present invention;

FIG. 2 is a top view of the cam to be machined of FIG. 1 in accordance with the present invention;

FIG. 3 is a schematic structural diagram of a cam to be machined according to the present invention;

FIG. 4 is a schematic structural view of a nut mandrel tool clamping cam of the present invention;

FIG. 5 is a schematic structural view of a gland mandrel tool clamping cam of the present invention;

FIG. 6 is a flow chart of a method for manufacturing a thin block cam with a stepped hole according to the present invention;

in the figure: 1-cam, 101-small diameter through hole, 102-large diameter through hole, 103-inclined hole, 104-thin block edge; 2-nut mandrel tool, 201-step mandrel I, 202-step positioning surface I, 203-gasket, 204-nut, 205-center hole, 206-external thread I; 3-a gland mandrel tool 301-a step mandrel II, 3011-a step positioning surface II, 302-a gland 303-an external thread II; 304-internal thread, 305-central relief hole, 306-compression boss.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to fig. 1 to 6 in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

(as shown in fig. 6) the method for processing the thin block type cam with the stepped hole comprises the following steps:

step S1, machining a small-diameter through hole of the cam: finish turning a small diameter through hole 101 in a stepped bore of the cam 1 (i.e., as shown in fig. 1)

) (ii) a And the small-diameter through hole 101 is processed into a through hole concentric with the cam 1.

According to the invention, the small-diameter through hole 101 is firstly finely turned, then the cam 1 is assembled on the tool, and the matching length of the cam 1 and the later-described tool step mandrels I and II is increased, so that the grinding precision of the cam is improved.

In the above embodiment, further: the small-diameter through-hole 101 in step S1 has a dimensional tolerance class of H6 class.

Step S2, clamping the cam on the nut mandrel tool: clamping the cam 1 processed according to the step S1 on a nut mandrel tool 2, and specifically comprising the following steps:

step S201, finding direction: the cam 1 thin piece edge 104 is directed towards the nut mandrel tooling 2. So as to avoid the thin block edge 104 from being blocked and limiting the processing of the outer contour of the cam.

Step S202, centering: the small-diameter through hole 101 of the cam 1 is concentrically sleeved on a step mandrel I201 of the nut mandrel tool 2.

In the above embodiment, further: in step 202, the small-diameter through hole 101 and the step mandrel I201 are installed in an interference fit mode. The installation of interference fit guarantees the clamping concentricity.

Step S203, assembling: a washer 203 and a nut 204 are sleeved on the stepped mandrel I201 in sequence. The spacer 203 is a spacer having a certain axial thickness.

Step S204, compressing and fixing: the nut 204 is screwed on an external thread I206 formed at the outer side shaft end of the step mandrel I201; the clamping device is fixed and assembled by adopting thread pressing, is simple to operate, and is convenient to clamp and disassemble. Nut 204 is tightened until nut 204 and washer 203 concentrically and axially compress and fix cam 1 on horizontal step locating surface i 202 of step mandrel i 201.

It can be seen that: the horizontally arranged step positioning surface I202 ensures that the cam cannot incline when a machine tool grinds the cam contour line, and ensures the symmetry of the long and short shaft sizes of the cam and the straightness of a bus; meanwhile, the rigidity of the step mandrel I201 of the step structure is increased, the vibration during cam grinding is reduced, and the cam grinding precision is improved.

Step S3, processing the outer contour of the cam: because two sides of the shaft end of the step mandrel I201 in the nut mandrel tool 2 are respectively provided with a central hole 205.

The center hole 205 of the nut mandrel tool 2 with the cam 1 clamped is clamped concentrically with a chuck and a tip of a cam grinding machine tool; the outer contour of the cam 1 is then machined using a cam grinder.

Therefore, the central hole 205 is formed at the end of the I shaft of the step mandrel of the nut mandrel tool 2, and the central hole 205 of the tool is positioned and clamped on a cam grinding machine by using a chuck and a tip, so that the cam, the tool and the contour line center of the grinding cam of the machine tool are well positioned, and the machining precision is ensured. The practice is as follows: the nut mandrel tool 2 can ensure that the precision of a thin block type cam wheel mill with a stepped hole reaches 0.005 mm.

Step S4, removing the cam: firstly, removing the nut mandrel tool 2 from a cam grinding machine; and then the cam 1 is detached from the nut mandrel tool 2.

Step S5, clamping the cam on the gland mandrel tool: clamping the cam 1 processed in the step S4 on a gland mandrel tool 3, and specifically comprises the following steps:

step S501, finding direction: the cam 1 is facing the slab edge 104 towards the outside. Clamping towards the outside is carried out in order to machine a large-diameter through hole 102 (i.e. the hole shown in figure 1) on the other side of the cam 1

)。

Step S502, centering: and concentrically sleeving the small-diameter through hole 101 of the cam 1 on a step mandrel II 301 of the gland mandrel tool 3. The cam is ensured to be concentrically clamped on the gland mandrel tool.

In the above embodiment, further: and in the step S502, the small-diameter through hole 101 and the step mandrel II 301 are installed in a transition fit mode.

Step S503, assembling: and screwing the internal thread 304 formed on the gland 302 into the external thread II 303 formed on the gland mandrel tool 3 in an adaptive manner. Specifically, the external thread II 303 is arranged at the large-diameter end of the step mandrel II 301.

Step S504, compressing and fixing: and tightening the gland 302 until the gland 302 concentrically and axially compresses and fixes the cam 1 on the horizontal step positioning surface II 3011 of the step mandrel II 301.

The gland 302 is centrally formed with a central relief hole 305, the central relief hole 305 being used for machining the large diameter through hole 102.

Step S6, processing the large-diameter through hole of the cam: the large diameter bore 102 of cam 1 is turned through the central relief hole 305 of gland 302.

In the above embodiment, further: after the large-diameter through hole 102 of the cam is machined in the step S6, the gland mandrel tool 3 is continuously used for clamping the cam 1 to machine the inclined hole 103 at the outer shaft end of the large-diameter through hole 102 of the cam 1.

In the above embodiment, further: in step S6, a pressing boss 306 is formed at the inner edge of the shaft end of the central avoidance hole 305; the compression boss 306 fits into and avoids the slab edge 104 of cam 1 to axially compress cam 1.

It should be noted that: (see fig. 5 and 1)

dimensions

6b and 6c of the compression boss 306, and dimension 6b of the compression boss 306 on the gland and dimension 1 of the cam 1 shown in fig. 1

Equivalent; the dimension 6c of the pressing boss 306 on the gland 6 is equal to the dimension of the cam 1 shown in fig. 1

Equivalent; therefore, when the pressing cover 302 presses the cam 1, the pressing cover cannot be pressed at the structural weak part of the cam 1, so that the cam 1 is prevented from being inclined and deformed.

The invention also comprises a processing tool of the thin block type cam with the stepped hole, which is used in the processing method of the thin block type cam with the stepped hole.

The machining tool for the thin block type cam with the stepped hole comprises a nut mandrel tool 2 and a gland mandrel tool 3.

The nut mandrel tool 2 is used for conveniently processing the outer contour of the cam. Gland dabber frock 3 is used for conveniently processing the step hole of cam.

The nut mandrel tool 2 and the gland mandrel tool 3 ensure the processing symmetry degree of the cam and simultaneously ensure the processing precision of the cam stepped hole.

(as shown in fig. 4), the nut mandrel tool 2 is composed of a step mandrel i 201, a gasket 203 and a nut 204. Therefore, the number of the tool components is simple, the structure is simple, the processing and the use are convenient, and the tool is economical and practical.

The step mandrel I201 is provided with a horizontal step positioning surface I202. The step mandrel I201 is concentrically and horizontally sleeved with the positioning cam 1 through a step positioning surface I202.

The step positioning surface I202 ensures the levelness of cam assembly and prevents the cam from inclining; improve I201 structural strength of step dabber simultaneously.

The step positioning surface I202 of the step mandrel I201 provides positioning for the inner side of the end of the cam shaft, and cooperates with the interference fit and the combined action of the step mandrel I201 and the small-diameter through hole 101 of the cam 1, so that the cam cannot be inclined when a machine tool grinds the cam contour line, and the symmetry of the long and short axis sizes of the cam and the straightness of a bus are ensured; meanwhile, the rigidity of the step mandrel I with the step structure is increased, the vibration of the cam during grinding is reduced, and the cam grinding precision is improved.

The shaft end of the step mandrel I201 is provided with an external thread I206; the nut 204 is screwed on the matching external thread I206 to fix the cam 1 between the gasket 203 and the step mandrel I201 in a horizontally concentric axial compression mode.

In the above embodiment, further: the center of the shaft end of the step mandrel I201 is concentrically provided with a central hole 205.

When in use: the center hole 205 of the nut mandrel tool 2 with the cam 1 clamped is clamped concentrically with a chuck and a tip of a cam grinding machine tool; the outer contour of the cam 1 is then machined using a cam grinder.

Therefore, the central hole 205 is formed at the end of the I shaft of the step mandrel of the nut mandrel tool 2, and the central hole 205 of the tool is positioned and clamped on a cam grinding machine by using a chuck and a tip, so that the cam, the tool and the contour line center of the grinding cam of the machine tool are well positioned, and the machining precision is ensured. The practice is as follows: the nut mandrel tool 2 can ensure that the precision of a thin-block type cam grinder with a stepped hole reaches 0.005 mm.

(as shown in fig. 5) the gland mandrel tool 3 consists of a step mandrel II 301 and a gland 302. The number of the tool components is simple, the structure is simple, the processing and the use are convenient, and the tool is economical and practical.

The gland 302 is concentrically formed with a central relief hole 305 in the center. The center relief hole 305 is used to machine a cam step hole.

And the step mandrel II 301 is provided with a horizontal step positioning surface II 3011. The step positioning surface II 3011 is used for ensuring horizontal clamping of the cam and preventing the cam from inclining.

And the step mandrel II 301 is concentrically and horizontally sleeved with the positioning cam 1 through a step positioning surface II 3011.

The step mandrel II 301 of the gland mandrel tool 3 is cooperated with the step positioning surface II 3011 to concentrically press the fixed cam 1; the cam is accurately and reliably positioned concentrically.

The inner side of the cover body of the gland 302 is provided with an internal thread 304; an external thread II 303 is formed on the outer side of the shaft body of the step mandrel II 301; the internal thread 304 is screwed and matched with the external thread II 303 to fix the cam 1 between the gland 302 and the step mandrel II 301 in a horizontally concentric axial compression mode. The screw thread is screwed to adapt to a mode of pressing and fixing, and the assembly is simple and efficient.

In the above embodiment, further: the cam 1 is installed with the step mandrel I201 in an interference fit mode; and the cam 1 and the step mandrel II 301 are installed in a transition fit mode.

In the above embodiment, further: a pressing boss 306 is arranged on the inner side edge of the shaft end of the central avoidance hole 305; the compression boss 306 fits into and avoids the slab edge 104 of cam 1 to axially compress cam 1.

It should be noted that: (see fig. 5 and 1)

dimensions

It can be seen that the compression boss 206 on the inside of the gland 302 prevents the cam 1 from pressing against the thin piece edge 104, and prevents the cam from being deformed by tilting during the machining process.

From the above description it can be found that: the invention meets the high-precision processing requirement of a thin-block cam with an axial length less than 10mm, such as a stepped hole; harmonic waves such as the symmetry degree of a cam, the straightness degree and the parallelism degree of a bus, the tolerance grade of a stepped hole and the form and position tolerance circular run-out can all meet high standard requirements; simple structure, convenient assembling, economical and practical, and is suitable for popularization.

All the embodiments in the present specification are described in a related manner, and the same and similar parts among the embodiments may be referred to each other, and each embodiment focuses on the differences from the other embodiments.

The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. The processing method of the thin block type cam with the stepped hole is characterized by comprising the following steps of:

s1, machining a small-diameter through hole of the cam: finely turning a small-diameter through hole (101) in a stepped hole of the cam (1); machining the small-diameter through hole (101) into a through hole concentric with the cam (1);

s2, clamping the cam on the nut mandrel tool: clamping the cam (1) processed according to the step S1 on a nut mandrel tool (2), and specifically comprises the following steps:

s201, finding a direction: facing the edge (104) of the thin block of the cam (1) to the nut mandrel tool (2);

s202, centering: concentrically sleeving a small-diameter through hole (101) of a cam (1) on a step mandrel I (201) of a nut mandrel tool (2);

s203, assembling: a gasket (203) and a nut (204) are sleeved on the step mandrel I (201) in sequence;

s204, compressing and fixing: the nut (204) is screwed on an external thread I (206) arranged at the outer side shaft end of the step mandrel I (201); screwing down the nut (204) until the cam (1) is concentrically and axially compressed and fixed on a horizontal step positioning surface I (202) of the step mandrel I (201) by the nut (204) and the gasket (203);

s3, processing the outer contour line of the cam: because the two sides of the shaft end of the step mandrel I (201) in the nut mandrel tool (2) are respectively provided with a central hole (205); the method comprises the following steps of firstly, concentrically clamping a central hole (205) of a nut mandrel tool (2) for clamping a cam (1) with a chuck and a tip of a cam grinding machine; then, processing the outer contour line of the cam (1) by using a cam grinding machine tool;

s4, removing the cam: firstly, removing the nut mandrel tool (2) from a cam grinding machine; then the cam (1) is detached from the nut mandrel tool (2);

s5, clamping the cam on the gland mandrel tool: clamping the cam (1) processed in the step S4 on a gland mandrel tool (3), and specifically comprises the following steps:

s501, finding a direction: facing the thin block edge (104) of the cam (1) towards the outside;

s502, centering: concentrically sleeving a small-diameter through hole (101) of the cam (1) on a step mandrel II (301) of a gland mandrel tool (3);

s503, assembling: screwing the internal thread (304) formed on the gland (302) into the external thread II (303) formed on the gland mandrel tool (3) in a matching and connecting manner;

s504, compressing and fixing: screwing down the gland (302) until the gland (302) concentrically and axially compresses and fixes the cam (1) on a horizontal step positioning surface II (3011) of the step mandrel II (301);

s6, machining a large-diameter through hole of the cam: and (3) the large-diameter through hole (102) of the cam (1) is turned after penetrating through the center avoidance hole (305) of the gland (302).

2. The method of processing a slab cam with a stepped hole according to claim 1, wherein: and S6, after the large-diameter through hole (102) of the cam is machined, the gland mandrel tool (3) is continuously used for clamping the cam (1) to machine the inclined hole (103) at the outer side shaft end of the large-diameter through hole (102) of the cam (1).

3. The method of processing a slab cam with a stepped hole according to claim 1, wherein: the small diameter through hole (101) in the step S1 has a dimensional tolerance grade of H6.

4. The method of manufacturing a thin block cam with a stepped hole according to claim 1, wherein: in step 202, the small-diameter through hole (101) and the step mandrel I (201) are installed in an interference fit mode.

5. The method of processing a slab cam with a stepped hole according to claim 1, wherein: and in the step S502, the small-diameter through hole (101) and the step mandrel II (301) are installed in a transition fit mode.

6. The method of processing a slab cam with a stepped hole according to claim 1, wherein: in the step S6, a pressing boss (306) is arranged on the inner side edge of the shaft end of the central avoidance hole (305); the pressing boss (306) is adapted to and avoids the thin block edge (104) of the cam (1) to axially press the cam (1).

7. The tooling for machining a stepped-hole thin-block cam used in the method for machining a stepped-hole thin-block cam according to any one of claims 1 to 6, characterized in that: the processing tool of the thin block type cam with the stepped hole comprises a nut mandrel tool (2) and a gland mandrel tool (3);

the nut mandrel tool (2) is composed of a step mandrel I (201), a gasket (203) and a nut (204); the step mandrel I (201) is provided with a horizontal step positioning surface I (202); the step mandrel I (201) is concentrically and horizontally sleeved with the positioning cam (1) through the step positioning surface I (202); an external thread I (206) is formed at the shaft end of the step mandrel I (201); the nut (204) is screwed and matched with the external thread I (206) so as to compress and fix the cam (1) between the gasket (203) and the step mandrel I (201) in a horizontal concentric axial direction;

the gland mandrel tool (3) consists of a step mandrel II (301) and a gland (302); a central avoidance hole (305) is concentrically formed in the center of the gland (302); the step mandrel II (301) is provided with a horizontal step positioning surface II (3011); the step mandrel II (301) is concentrically and horizontally sleeved with the positioning cam (1) through a step positioning surface II (3011); the inner side of the cover body of the gland (302) is provided with internal threads (304); an external thread II (303) is formed on the outer side of the shaft body of the step mandrel II (301); the internal thread (304) is screwed and matched with the external thread II (303) to fix the cam (1) between the gland (302) and the step mandrel II (301) in a horizontally concentric axial compression mode.

8. The tooling for machining the thin block type cam with the stepped hole according to claim 7, wherein: the cam (1) is installed with the step mandrel I (201) in an interference fit manner; the cam (1) and the step mandrel II (301) are installed in a transition fit mode.

9. The tooling for machining the thin block type cam with the stepped hole according to claim 7, wherein: a pressing boss (306) is arranged on the inner side edge of the shaft end of the central avoidance hole (305); the pressing boss (306) is adapted to and avoids the thin block edge (104) of the cam (1) to axially press the cam (1).

10. The tooling for machining the thin block type cam with the stepped hole according to claim 7, wherein: the center of the shaft end of the step mandrel I (201) is concentrically provided with a central hole (205).