CN220073312U - Pulling boring rolling head - Google Patents

Abstract

The utility model relates to the technical field of machining tools, in particular to a pull boring roller head, which aims to solve the problem that the roughness of an inner hole of a grinded cylinder body cannot meet the requirement of high-precision production when the pull boring roller head in the traditional pull boring mode is used for machining.

Description

Pulling boring rolling head

Technical Field

The utility model relates to the technical field of machining tools, in particular to a pull boring roller head.

Background

The cylinder body of one of the key parts of the hydraulic support needs a large amount, and the inner hole processing of the cylinder body is a key process of the part. The processing method of the inner hole comprises two steps of push boring honing and push boring rolling, and in recent years. The rolling processing belongs to chipless processing, and the designed boring head and the rolling head are combined with boring processing, so that the boring processing is called boring rolling, drawing, boring and rolling, is more suitable for the inner hole processing of a cylinder body, and along with the development of a device instrument to high precision, the inner hole roughness of the cylinder body required to be manufactured puts forward higher requirements, and when the boring roller head in the existing boring mode is used for processing, the inner hole roughness of the cylinder body cannot meet the high-precision production requirement.

Disclosure of Invention

The purpose of the patent of the utility model is that: the utility model provides a pull boring roller head, which aims to solve the problem that the roughness of an inner hole of a grinded cylinder body cannot meet the requirement of high-precision production when the pull boring roller head is processed in the existing pull boring mode.

In order to achieve the aim, the pull boring roller head comprises a main body, a bearing seat assembly, a first ball assembly, a first pad sleeve assembly, a second ball assembly, a roller assembly, a second pad sleeve assembly, a first round nut, a second round nut and a joint;

the main part is the step shaft, is equipped with the location ladder in the middle part of the main part, and the diameter of main part is the echelonment that the gradual change was reduced to the both ends of main part along the location ladder, and the one end of main part is equipped with the connecting hole, and bearing frame subassembly, ball subassembly one, pad cover subassembly one, ball subassembly two, roller subassembly, pad cover subassembly two, round nut one and round nut two are in order the suit in the main part along the one end of the location ladder of main part to the main part, the bearing frame subassembly hugs closely the side terminal surface of location ladder, uses round nut one and round nut two to be used for preventing each part in the main part not hard up, connects and the connecting hole of main part to be connected.

Further, a rubber pad sleeved on the joint is arranged between the joint and the main body.

Still further, the bearing seat assembly comprises a strong thrust bearing I, a spacer ring, a bearing seat, a nut, a guide sleeve and a plurality of oil seal rings;

the high thrust bearing is sleeved outside the main body, the spacer ring is sleeved outside the high thrust bearing, the bearing seat is sleeved outside the spacer ring, the outer diameter of the bearing seat is three sections of steps gradually reduced from one end to the other end, the other end of the inner ring of the bearing seat is provided with an edge ring extending inwards, the edge ring is sleeved outside the main body, the nut and the plurality of oil seal rings are sleeved on the middle steps of the bearing seat, the plurality of oil seal rings are positioned between the steps at one end of the bearing seat and the nut, the bearing seat is in threaded connection with the nut, the other end of the bearing seat is clung to the end face of one end of the positioning step, and the guide sleeve is sleeved outside the steps at the other end of the bearing seat and the positioning step. The nut is also connected and fastened with the middle step of the bearing seat through a jackscrew.

Still further, the uide bushing still has the ladder of bearing frame other end through the bolt fastening.

Further, the first ball assembly comprises a ball support A, a ball support B, at least one ball support C, at least two first gaskets, at least two first ball isolating rings and at least two first rings of balls;

the ball support A, the ball support B and the ball supports C are sleeved outside the main body, grooves are formed in the side parts of the ball support A and sleeved outside the first strong thrust bearing, the ball supports C are arranged between the ball support A and the ball support B, and a first gasket is respectively arranged between the ball support A and the ball support C, between every two ball supports C and between the ball support B and the ball support C; a circle of first balls are respectively arranged between the outer ring of the ball support A and the outer ring of the ball support C, between the outer rings of every two ball supports C and between the outer ring of the ball support B and the outer ring of the ball support C; each circle of first balls comprises a plurality of first balls, each ball isolating ring is sleeved outside one circle of first balls, and the first balls penetrate through the first ball isolating rings.

Still further, the first mat assembly comprises a first mat, a first washer and a plurality of first mats;

the first cushion cover is sleeved outside the main body, and the first cushion cover is a T-shaped cushion cover; the first gasket and the first felts are sleeved outside the first gasket, and the first felts are positioned between the first gasket and the first gasket.

Further, the second ball assembly comprises two side ball supports, at least one middle ball support, at least two gaskets, at least two ball isolating rings and a plurality of rings of balls;

the two side ball supports and at least one middle ball support are sleeved outside the main body, the middle ball support is arranged between the two side ball supports, and a second gasket is respectively arranged between the side ball support and the middle ball support and between the two middle ball supports; a circle of balls II are respectively arranged between the side ball support and the middle ball support and between the two middle ball supports; each circle of second balls comprises a plurality of second balls, each second ball isolating ring is sleeved outside one circle of second balls, and the second balls penetrate through the second ball isolating rings.

Still further, the roller assembly comprises a second gasket, a taper sleeve, a second gasket, a first retainer ring, a second strong thrust bearing, a roller spacer ring, a plurality of rollers and a plurality of adjusting nuts;

the roller spacer ring left end cover is on the pad cover two, and the inside cartridge in roller spacer ring left end is connected with a plurality of rollers that set up along circumferencial direction equipartition, and roller spacer ring right-hand member cover is on the taper sleeve, and the inside cartridge in roller spacer ring right-hand member is connected with a plurality of rollers that set up along circumferencial direction equipartition, and every roller corresponds a roller, pad cover two and taper sleeve outside from left to right suit at least two adjusting nut, packing ring, strong thrust bearing two, roller spacer ring, retaining ring one and at least two adjusting nut in proper order.

Further, the second cushion sleeve assembly comprises a third cushion sleeve, a third gasket, a third round nut and a plurality of second felt rings;

the third cushion sleeve is sleeved outside the main body, and is a T-shaped cushion sleeve; the round nut III, the gasket III and the felt rings II are sleeved outside the cushion sleeve III, and the felt rings II and the cushion sleeve III are positioned between the round nut III and the cushion sleeve III; the second felts are positioned between the third cushion sleeve and the third cushion ring.

Further, the first, second and third balls are each made of GCr 15.

The beneficial effects are that:

the scheme changes the hard alloy guide strip in the common boring head into the roller component I, the ball component II and the roller component, changes sliding friction into rolling friction, has rolling action besides guiding action, and also has a plurality of circles of rolling bodies, so that the rolling effect of the boring head is increased, the rolling action of a plurality of strokes is achieved in one stroke, and plastic deformation of the cylinder is improved when the cylinder is processed.

Drawings

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

FIG. 1 is a schematic perspective view of a pull boring roller head according to the present utility model;

FIG. 2 is a schematic perspective view of the main body of the present utility model;

FIG. 3 is a perspective view of a bearing housing assembly of the present utility model;

FIG. 4 is a second perspective view of the bearing housing assembly of the present utility model;

FIG. 5 is a schematic perspective view of a ball assembly I of the present utility model;

FIG. 6 is a schematic perspective view of a ball assembly I of the present utility model;

FIG. 7 is a schematic view of a first ball assembly without a first ball spacer ring and a first ball;

FIG. 8 is a perspective view of a first spacer assembly of the present utility model;

FIG. 9 is a schematic perspective view of a second ball assembly according to the present utility model;

FIG. 10 is a schematic view of a second ball assembly of the present utility model without a second ball spacer ring and a second ball;

FIG. 11 is a schematic perspective view of a roller assembly of the present utility model;

FIG. 12 is a second perspective view of the roller assembly of the present utility model;

fig. 13 is a schematic perspective view of a second cushion cover assembly according to the present utility model.

Detailed Description

The first embodiment is as follows: a pull boring rolling head comprises a main body 1, a bearing seat assembly 2, a ball assembly I3, a cushion sleeve assembly I4, a ball assembly II 5, a roller assembly 6, a cushion sleeve assembly II 7, a round nut I8, a round nut II 9 and a joint 10;

the main part 1 is the step shaft, and main part 1 middle part is equipped with the location ladder, and the diameter of main part 1 is the ladder form that the gradual change was reduced to the both ends of main part 1 along the location ladder, and the one end of main part 1 is equipped with the connecting hole, and bearing frame subassembly 2, ball subassembly one 3, pad cover subassembly one 4, ball subassembly two 5, roller subassembly 6, pad cover subassembly two 7, round nut one 8 and round nut two 9 follow the one end suit in order of main part 1 to main part 1 on main part 1, the side terminal surface of location ladder is hugged closely to bearing frame subassembly 2, uses round nut one 8 and round nut two 9 to be used for preventing each part on the main part 1 not hard up, and joint 10 is connected with the connecting hole of main part 1.

In this embodiment, the following will be described: the bearing seat assembly, the first ball assembly, the first cushion sleeve assembly, the second ball assembly, the roller assembly, the second cushion sleeve assembly, the first round nut, the second round nut and the joint are all arranged on the main body, the bearing seat assembly is used for connecting the main body with the first ball assembly, the second ball assembly and the roller assembly can roll the inner wall of the cylinder to be processed, the first cushion sleeve assembly and the second cushion sleeve assembly are used for filling up gaps on the main body and dispersing pressure born by the main body, after the first round nut and the second round nut are screwed, the first round nut and the second round nut are used for preventing each part on the main body from loosening, the joint is used for connecting other workpieces after being connected, the other workpieces are not in the consideration range of the utility model, in general, the joint is used for connecting a tool bit, and one end of the main body is used for connecting a connecting shaft/a connecting rod/a fixture of a lathe or a boring machine.

The second embodiment is as follows: a pull boring roller head is arranged between a joint 10 and a main body 1, and a rubber pad 13 sleeved on the joint 10 is arranged between the joint and the main body 1.

In this embodiment, the following will be described: the rubber pad is used for improving the connection tightness of the chicken head and the main body.

Other embodiments are the same as the first embodiment.

And a third specific embodiment: the bearing seat assembly 2 comprises a strong thrust bearing I2-1, a spacing ring 2-2, a bearing seat 2-3, a nut 2-5, a guide sleeve 2-6 and a plurality of oil seal rings 2-4;

the high thrust bearing I2-1 is sleeved outside the main body 1, the spacer ring 2-2 is sleeved outside the high thrust bearing I2-1, the bearing seat 2-3 is sleeved outside the spacer ring 2-2, the outer diameter of the bearing seat 2-3 is three steps gradually reduced from one end to the other end, the other end of the inner ring of the bearing seat 2-3 is provided with an edge ring extending inwards, the edge ring is sleeved outside the main body 1, the nut 2-5 and the plurality of oil seal rings 2-4 are sleeved on the middle steps of the bearing seat 2-3, the plurality of oil seal rings 2-4 are positioned between the steps at one end of the bearing seat 2-3 and the nut 2-5, the bearing seat 2-3 is in threaded connection with the nut 2-5, the other end of the bearing seat 2-3 is clung to the end face at one end of the positioning step, and the guide sleeve 2-6 is sleeved outside the steps at the other end of the bearing seat 2-3. The nut 2-5 is also connected and fastened with the middle step of the bearing seat 2-3 through a jackscrew.

In this embodiment, the following will be described: the assembly is used for connecting the main body with the first ball assembly.

Other embodiments are the same as the first embodiment.

The specific embodiment IV is as follows: the pull boring rolling head is characterized in that the guide sleeve 2-6 and the ladder at the other end of the bearing seat 2-3 are fastened through bolts.

In this embodiment, the following will be described: the guide sleeve and the bearing seat are fastened through bolts to form a whole, so that relative movement of the guide sleeve and the bearing seat is avoided.

Other embodiments are the same as the third embodiment.

Fifth embodiment: a pull boring roller head, wherein the ball assembly I3 comprises a ball support A3-1, a ball support B3-2, at least one ball support C3-3, at least two gaskets I3-4, at least two ball isolating rings I3-5 and at least two circles of balls I3-6;

the ball supports A3-1, the ball supports B3-2 and the ball supports C3-3 are all sleeved outside the main body 1, grooves are formed in the side parts of the ball supports A3-1 and are sleeved outside the strong thrust bearings A2-1, the ball supports C3-3 are arranged between the ball supports A3-1 and the ball supports B3-2, and a gasket A3-4 is respectively arranged between the ball supports A3-1 and the ball supports C3-3, between every two ball supports C3-3 and between the ball supports B3-2 and the ball supports C3-3; a circle of balls one 3-6 is respectively arranged between the outer ring of the ball support A3-1 and the outer ring of the ball support C3-3, between the outer rings of every two ball supports C3-3 and between the outer ring of the ball support B3-2 and the outer ring of the ball support C3-3; each circle of balls one 3-6 comprises a plurality of balls one 3-6, each ball isolating ring one 3-5 is sleeved outside one circle of balls one 3-6, and the balls one 3-6 penetrate through the ball isolating ring one 3-5.

In this embodiment, the following will be described: the parts form a ball assembly I, and the inner wall of the oil cylinder to be processed can be rolled after the ball rotates.

Other embodiments are the same as the fourth embodiment.

Specific embodiment six: the first cushion sleeve assembly 4 comprises a first cushion sleeve 4-1, a first gasket 4-2 and a plurality of first felt rings 4-3;

the first cushion cover 4-1 is sleeved outside the main body 1, and the first cushion cover 4-1 is a T-shaped cushion cover; the first gasket 4-2 and the plurality of first felts 4-3 are sleeved outside the first gasket 4-1, and the plurality of first felts 4-3 are positioned between the first gasket 4-1 and the first gasket 4-2.

In this embodiment, the following will be described: in this embodiment, the following will be described: the first cushion sleeve, the first gasket and the first plurality of felt rings form a first cushion sleeve assembly for filling up the gap on the main body and dispersing the pressure born by the main body.

Other embodiments are the same as the fifth embodiment.

Seventh embodiment: the second ball assembly 5 comprises two side ball supports 5-1, at least one middle ball support 5-3, at least two gaskets 5-4, at least two ball isolating rings 5-5 and a plurality of rings of balls 5-2;

the two side ball supports 5-1 and at least one middle ball support 5-3 are sleeved outside the main body 1, the middle ball support 5-3 is arranged between the two side ball supports 5-1, and a gasket two 5-4 is respectively arranged between the side ball support 5-1 and the middle ball support 5-3 and between the two middle ball supports 5-3; a circle of balls II 5-2 are respectively arranged between the side ball support 5-1 and the middle ball support 5-3 and between the two middle ball supports 5-3; each circle of second balls 5-2 comprises a plurality of second balls 5-2, each second ball isolating ring 5-5 is sleeved outside one circle of second balls 5-2, and the second balls 5-2 penetrate through the second ball isolating rings 5-5.

In this embodiment, the following will be described: the parts form a ball assembly II, and the ball assembly II can roll the inner wall of the oil cylinder to be processed after rotating.

The other embodiments are the same as the sixth embodiment.

Eighth embodiment: the roller assembly 6 comprises a second gasket sleeve 6-1, a taper sleeve 6-2, a second gasket ring 6-3, a first check ring 6-4, a second strong thrust bearing 6-5, a roller isolating ring 6-6, a plurality of rollers 6-7, a plurality of rollers 6-8 and a plurality of adjusting nuts 6-9;

the left end of the roller isolating ring 6-6 is sleeved on the cushion sleeve II 6-1, a plurality of rollers 6-7 uniformly distributed along the circumferential direction are inserted and connected inside the left end of the roller isolating ring 6-6, the right end of the roller isolating ring 6-6 is sleeved on the taper sleeve 6-2, a plurality of rollers 6-8 uniformly distributed along the circumferential direction are inserted and connected inside the right end of the roller isolating ring 6-6, each roller 6-8 corresponds to one roller 6-7, and at least two adjusting nuts 6-9, gaskets 6-3, strong thrust bearings II 6-5, roller isolating rings 6-6, a retainer ring I6-4 and at least two adjusting nuts 6-9 are sequentially sleeved outside the cushion sleeve II 6-1 and the taper sleeve 6-2 from left to right.

In this embodiment, the following will be described: the parts form a roller assembly, and the roller can roll the inner wall of the oil cylinder to be processed after rotating.

Other embodiments are the same as the seventh embodiment.

Detailed description nine: the second pad sleeve component 7 comprises a third pad sleeve 7-1, a third washer 7-2, a third round nut 7-4 and a plurality of second felt rings 7-3;

the third cushion cover 7-1 is sleeved outside the main body 1, and the third cushion cover 7-1 is a T-shaped cushion cover; the round nut III 7-4, the gasket III 7-2 and the plurality of felt rings II 7-3 are sleeved outside the cushion sleeve III 7-1, and the plurality of felt rings II 7-3 and the cushion sleeve III 7-1 are positioned between the round nut III 7-4 and the cushion sleeve III 7-1; a plurality of second felt rings 7-3 are positioned between the third cushion sleeve 7-1 and the third cushion ring 7-2.

In this embodiment, the following will be described: the third cushion sleeve, the third gasket, the third round nut and the second felt rings form a second cushion sleeve assembly for filling up the gap on the main body and dispersing the pressure born by the main body.

Other embodiments are the same as embodiment eight.

Detailed description ten: a pull boring roller head, ball one 3-6, ball two 5-2 and roller 6-7 are all made of GCr 15.

In this embodiment, the following will be described: the first ball, the second ball and the roller are all made of GCr15 and have enough hardness.

Other embodiments are the same as embodiment eight.

Application examples:

during the refitting, the tailstock is removed and changed into a boring bar seat, a square tool rest and a transverse feed slide carriage on the carriage are detached and replaced by an oil delivery device which has the functions of cooling, guiding and clamping workpieces,

the lathe spindle chuck is provided with a sleeve and a flange with a 90 DEG conical surface, the center line of a boring rod hole of the boring roller head and the center line of the lathe spindle are adjusted to be equal in height, the coaxiality error of the boring rod of the boring roller head and the lathe spindle is not more than 0.02mm, the coaxiality error of the boring rod of the boring roller head is not more than 0.02mm,

the 45 chamfer angle of the outer circle of the cylinder body of the cylinder to be processed is used as a positioning and clamping reference, the workpiece is supported and clamped by a head receiving disc and a receiving disc on an oil conveyer,

cutting cooling liquid is input from a side port of the oil delivery device, and the inner cavity is drawn to the boring roller head along the flow direction of the boring bar, so that cutting heat and chips are taken away;

the workpiece rotates during processing, and the cutter moves linearly, so that the wall thickness of the oil cylinder is uniform, and the linearity of the oil cylinder can be ensured.

During machining, power drives the oil cylinder through rotation of the head receiving disc, machining allowance is reserved for an inner hole of the rough machining oil cylinder by 0.4 mm, machining allowance is reserved for an inner hole of the finish machining oil cylinder by 0.05 mm, the first ball, the second ball and the roller are driven to rotate by friction force of an inner hole wall of the oil cylinder, the outer circle of the pull boring roller head rolls along, an original wave crest of the inner surface of the machined inner hole of the oil cylinder is rolled by the first ball, the second ball and the roller, crystal grains are displaced along the movement direction of the roller, and the crystal grains are lengthened to fill microscopic wave troughs.

The materials of the ball I, the ball II and the roller are GCr15, and the heat treatment quenching hardness is HRC 62-66.

Claims (10)

1. The pull boring rolling head is characterized in that: the novel bearing comprises a main body (1), a bearing seat assembly (2), a ball assembly I (3), a cushion sleeve assembly I (4), a ball assembly II (5), a roller assembly (6), a cushion sleeve assembly II (7), a round nut I (8), a round nut II (9) and a joint (10);

the main body (1) is a stepped shaft, a positioning step is arranged in the middle of the main body (1), the diameter of the main body (1) is in a step shape which gradually reduces towards the two ends of the main body (1) along the positioning step, one end of the main body (1) is provided with a connecting hole, a bearing seat component (2), a ball component I (3), a cushion sleeve component I (4), a ball component II (5), a roller component (6), a cushion sleeve component II (7), a round nut I (8) and a round nut II (9) are sequentially sleeved on the main body (1) along the positioning step of the main body (1) to one end of the main body (1), the bearing seat assembly (2) is tightly attached to the side end face of the positioning ladder, the round nut I (8) and the round nut II (9) are used for preventing each part on the main body (1) from loosening, and the joint (10) is connected with the connecting hole of the main body (1).

2. The pull boring head according to claim 1, wherein: a rubber pad (13) sleeved on the joint (10) is arranged between the joint (10) and the main body (1).

3. The pull boring head according to claim 1, wherein: the bearing seat assembly (2) comprises a strong thrust bearing I (2-1), a spacing ring (2-2), a bearing seat (2-3), a nut (2-5), a guide sleeve (2-6) and a plurality of oil seal rings (2-4);

the high thrust bearing I (2-1) is sleeved outside the main body (1), the spacer ring (2-2) is sleeved outside the high thrust bearing I (2-1), the bearing seat (2-3) is sleeved outside the spacer ring (2-2), the outer diameter of the bearing seat (2-3) is three sections of steps gradually shrinking from one end to the other end, the other end of the inner ring of the bearing seat (2-3) is provided with an edge ring extending inwards, the edge ring is sleeved outside the main body (1), the nut (2-5) and the plurality of oil seal rings (2-4) are sleeved on the middle steps of the bearing seat (2-3), the plurality of oil seal rings (2-4) are positioned between the steps at one end of the bearing seat (2-3) and the nuts (2-5), the bearing seat (2-3) is in threaded connection with the nuts (2-5), the other end of the bearing seat (2-3) is tightly attached to the end face of one end of the positioning step, and the guide sleeve (2-6) is sleeved outside the steps at the other end of the bearing seat (2-3) and the positioning step; the nut (2-5) is also connected and fastened with the middle part of the bearing seat (2-3) through a jackscrew in a step manner.

4. A pull boring roller head according to claim 3, wherein: the guide sleeve (2-6) is also provided with a step at the other end of the bearing seat (2-3) and is fastened by bolts.

5. A pull boring roller head according to claim 3, wherein: the first ball assembly (3) comprises a ball support A (3-1), a ball support B (3-2), at least one ball support C (3-3), at least two gaskets I (3-4), at least two ball isolating rings I (3-5) and at least two circles of balls I (3-6);

the ball bearing A (3-1), the ball bearing B (3-2) and the plurality of ball bearings C (3-3) are sleeved outside the main body (1), grooves are formed in the side parts of the ball bearings A (3-1) and sleeved outside the strong thrust bearing I (2-1), the plurality of ball bearings C (3-3) are arranged between the ball bearings A (3-1) and the ball bearings B (3-2), and a gasket I (3-4) is respectively arranged between the ball bearings A (3-1) and the ball bearings C (3-3), between every two ball bearings C (3-3) and between the ball bearings B (3-2) and the ball bearings C (3-3); a circle of first balls (3-6) are respectively arranged between the outer ring of the ball support A (3-1) and the outer ring of the ball support C (3-3), between the outer rings of every two ball supports C (3-3) and between the outer ring of the ball support B (3-2) and the outer ring of the ball support C (3-3); each circle of ball I (3-6) comprises a plurality of ball I (3-6), each ball isolating ring I (3-5) is sleeved outside one circle of ball I (3-6), and the ball I (3-6) passes through the ball isolating ring I (3-5).

6. The pull boring head according to claim 5, wherein: the first cushion cover component (4) comprises a first cushion cover (4-1), a first gasket (4-2) and a plurality of first felts (4-3);

the first cushion cover (4-1) is sleeved outside the main body (1), and the first cushion cover (4-1) is a T-shaped cushion cover; the first gasket (4-2) and the first felts (4-3) are sleeved outside the first gasket (4-1), and the first felts (4-3) are positioned between the first gasket (4-1) and the first gasket (4-2).

7. The pull boring head of claim 6, wherein: the ball assembly II (5) comprises two side ball supports (5-1), at least one middle ball support (5-3), at least two gaskets II (5-4), at least two ball isolating rings II (5-5) and a plurality of rings of balls II (5-2);

the two side ball supports (5-1) and at least one middle ball support (5-3) are sleeved outside the main body (1), the middle ball support (5-3) is arranged between the two side ball supports (5-1), and a gasket II (5-4) is respectively arranged between the side ball supports (5-1) and the middle ball support (5-3) and between the two middle ball supports (5-3); a circle of balls II (5-2) are respectively arranged between the side ball support (5-1) and the middle ball support (5-3) and between the two middle ball supports (5-3); each circle of ball second (5-2) comprises a plurality of ball second (5-2), each ball isolating ring second (5-5) is sleeved outside one circle of ball second (5-2), and the ball second (5-2) penetrates through the ball isolating ring second (5-5).

8. The pull boring head according to claim 7, wherein: the roller assembly (6) comprises a second cushion sleeve (6-1), a taper sleeve (6-2), a second gasket (6-3), a first check ring (6-4), a second strong thrust bearing (6-5), a roller isolating ring (6-6), a plurality of rollers (6-7), a plurality of rollers (6-8) and a plurality of adjusting nuts (6-9);

the roller isolating ring (6-6) is sleeved on the second cushion sleeve (6-1), a plurality of rollers (6-7) uniformly distributed along the circumferential direction are inserted and connected inside the left end of the roller isolating ring (6-6), the right end of the roller isolating ring (6-6) is sleeved on the taper sleeve (6-2), a plurality of rollers (6-8) uniformly distributed along the circumferential direction are inserted and connected inside the right end of the roller isolating ring (6-6), each roller (6-8) corresponds to one roller (6-7), and at least two adjusting nuts (6-9), a gasket (6-3), a second strong thrust bearing (6-5), a roller isolating ring (6-6), a first retainer ring (6-4) and at least two adjusting nuts (6-9) are sleeved outside the second cushion sleeve (6-1) and the taper sleeve (6-2) from left to right in sequence.

9. The pull boring head according to claim 8, wherein: the second cushion cover component (7) comprises a third cushion cover (7-1), a third gasket (7-2), a third round nut (7-4) and a plurality of second felt rings (7-3);

the third cushion cover (7-1) is sleeved outside the main body (1), and the third cushion cover (7-1) is a T-shaped cushion cover; the round nut III (7-4), the gasket III (7-2) and the plurality of the felt rings II (7-3) are sleeved outside the cushion sleeve III (7-1), and the plurality of the felt rings II (7-3) and the cushion sleeve III (7-1) are positioned between the round nut III (7-4) and the cushion sleeve III (7-1); a plurality of second felts (7-3) are arranged between the third cushion sleeve (7-1) and the third cushion ring (7-2).

10. The pull boring head according to claim 8, wherein: the first ball (3-6), the second ball (5-2) and the roller (6-7) are all made of GCr 15.