JP2002021984A - Mounting structure of pinion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide mounting structure of a pinion, in which leakage of lubricating oil is prevented, a degree of freedom of design is high, a radial direction dimension of, particularly, near a gear cutting portion of a bearing housing can be reduced. SOLUTION: A cylindrical worked portion 116 of a pinion body 106 is engaged with a cylinder guiding portion of a vertical shaft 104 so that a position in a radial direction of the pinion body 106 is regulated, (the center of the shaft can not shift). Torque transmission of the vertical shaft 104 to the pinion body 108 is realized by fixing of the knurling portion 118 of the pinion body 106 to a knurling crimp portion of the vertical shaft 104. A bolt 130 is screwed into the center of the shaft of the pinion body 106 so that slipping out of the pinion body 106 from the vertical shaft 104 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a driving shaft,
The present invention relates to a pinion mounting structure in which a connecting shaft is mounted so as to be rotatable integrally with the drive shaft, and a pinion body is mounted so as to be rotatable integrally with the connecting shaft.

[0002] In this specification, "pinion" includes the concept of "small roller" in addition to "small gear".

[0003]

2. Description of the Related Art When a pinion is formed at the tip of a drive shaft (for example, a motor shaft), a method of directly cutting gears on the motor shaft and, as shown in FIG. 1) a pinion main body 4 is mounted so as to be integrally rotatable via a key 3, and the pinion main body 4 is mounted on a casing (bearing case) 8 via a pair of bearings 6 and 7.

As shown in FIG. 5, a connecting shaft 14 is mounted on the driving shaft 10 via a key 12 so as to be integrally rotatable, and a pinion main body 18 is integrally rotatable on the connecting shaft 14 via a key 16. There is also proposed a structure to be mounted on a vehicle.

[0005] In this structure, the connecting shaft 14 is connected to the casing 20.
The axial position of the pair of bearings 21 and 22 for supporting the pinion main body 16 is regulated by retaining rings 24 and 26, and the stepped portion 18A of the pinion main body 18 comes into contact with the end 21A of the bearing 21 so that the pinion main body 16 Positioning with respect to the casing 20 is performed. On the other hand, through the connecting shaft 14 from the drive shaft 10 side, the bolt 28
Is screwed (screw-in), and the step 14A of the joint shaft 14 comes into contact with the end 22A of the bearing 22 by tightening the bolt 28, thereby positioning the joint shaft 14 in the axial direction with respect to the casing 20. It has become.

[0006]

However, in the conventional structure shown in FIG. 5, since the connecting shaft 14 and the pinion body 18 are integrated via the key 16 and the bolt 28, the structure shown in FIG. As indicated by the thick broken line, there is a problem that the lubricating oil of the unillustrated reduction mechanism may leak toward the drive shaft 2 through the gap around the key groove 16A and the gap around the bolt 28. Therefore, in order to prevent this, it was necessary to apply a sealant around the bolt 28 to prevent leakage of lubricating oil.

Further, since the keyway 16A needs to be formed on both the joint shaft 14 and the pinion main body 18, the shaft diameter DP1 of the pinion main body 18 and the outer diameter D of the joint shaft 14 are increased in terms of strength.
C1 needs to be thickened, and there is a problem that the radial size RK1 of the bearing case 20 in the vicinity of the gear cutting portion of the pinion body 18 tends to increase.

On the other hand, in the structure shown in FIG. 6, although the problem of leakage of the lubricating oil does not occur, since the pinion body 4 also serves as the connecting shaft, the degree of freedom in design is extremely low, and as a result, the total manufacturing There was a problem that costs increased. Further, in the structure shown in FIG. 6, the inner diameter DB2 of the bearing 6 (on the side where the gear cutting portion 4A of the pinion body 4 exists) must be larger than the maximum outer diameter DS2 of the gear cutting portion 4A due to the assembling relationship. Therefore, when the maximum outer diameter DC2 of the gear cutting portion 4A of the pinion body 4 is large, the radial size RK2 of the bearing case 8 near the gear cutting portion 4A also increases accordingly. There was a problem.

The present invention has been made in view of such conventional problems, and can prevent leakage of lubricating oil without applying a sealant, and has a high degree of freedom in design. An object of the present invention is to provide a pinion mounting structure capable of mounting a pinion body having a large maximum outer diameter of a gear cutting portion and reducing a radial dimension of a bearing case particularly near the gear cutting portion.

[0010]

SUMMARY OF THE INVENTION The present invention provides a pinion mounting structure in which a connecting shaft is mounted at the tip of a driving shaft so as to be rotatable integrally with the driving shaft, and a pinion body is mounted on the connecting shaft so as to be integrally rotatable. In the above, the pinion body has a head portion including a gear cutting portion that meshes with the next gear, a cylindrical processing portion formed in a cylindrical shape coaxially with the head portion, and a knurling process coaxial with the cylindrical processing portion. Knurl processing part,
The joint shaft is a cylindrical guide portion that regulates the radial position of the pinion body by guiding and inserting the cylindrical processing portion, and the torque of the joint shaft is reduced by press-fitting the knurling portion. A knurl crimping portion that can be transmitted to the pinion main body, and a bolt is screwed into the shaft center of the pinion main body through the connecting shaft from the drive shaft side, and the pinion main body comes out of the connecting shaft. The above problem is solved by preventing the above problem (claim 1).

In the present invention, the joint shaft and the pinion main body are basically formed separately from each other in consideration of design flexibility. With this configuration, when the drive shaft side (for example, the motor shaft side) is invariable, basically the same shaft and bearings that support it can be used, and by changing only the pinion main body, various types of shaft devices can be used. Can be easily obtained.

In the present invention, on the basis of this separate structure, the pinion main body is formed in a cylindrical shape coaxial with the head portion including a gear portion that meshes with the next gear. The cylindrical processing portion and a knurled portion coaxial with the cylindrical processing portion and knurled to have the same diameter or a slightly smaller diameter than the cylindrical processing portion are provided. On the other hand, the joint shaft is configured to include a cylindrical guide portion into which the cylindrical processing portion is guided and inserted, and a knurl crimping portion into which the knurl processing portion is press-fitted and inserted.

As a result, the radial position of the pinion main body is regulated by the engagement between the cylindrical processing portion of the pinion main body and the cylindrical guide portion of the joint shaft (the deviation of the axial center is prevented), and By fixing the knurled portion of the pinion body to the knurled crimping portion of the joint shaft, the torque of the joint shaft can be transmitted to the pinion body.

Further, in the present invention, since the bolt is screwed into the shaft center of the pinion body through the connecting shaft from the drive shaft side, the pinion body is prevented from coming off from the connecting shaft.

The structure around the bolt is basically the same as that shown in FIG.
However, the connection between the joint shaft and the pinion body is not the key connection, but the engagement between the cylindrical processing part and the cylindrical guide part, and the fixing between the knurl processing part and the knurl crimping part. , The problem of leakage of lubricating oil does not occur. Therefore, there is no need to apply a sealing agent.

The "cylindrical guide portion" and the "knurled crimping portion" in the present invention are defined conceptually corresponding to the "cylindrical processed portion" and the "knurled processed portion", respectively. As the structure, for example, a (single) concave portion having the same diameter may be simply formed continuously. Also, the order of forming the “cylindrical processed portion” and the “knurled processed portion” with respect to the “head portion” may be reversed. That is, "head part""knurledpart""cylindricalpart"
May be formed in this order.

The invention according to claim 2 is based on such a configuration and further improved. That is,
The invention according to claim 2 is that the cylindrical processing portion of the pinion body is formed in a cylindrical shape coaxially with the head portion and with a step, while the joint shaft abuts on the step. It is characterized in that it has a reference end portion at which the axial position of the pinion body with respect to the joint shaft is determined.

According to the present invention, the positioning of the pinion main body is realized by the contact between the step formed on the pinion main body and the reference end formed on the joint shaft.
Unlike the conventional example shown in Fig. 1, since the positioning is not performed by abutting the head portion of the pinion body and the bearing, the magnitude relationship between the head portion and the bearing does not need to depend on each other, and the design flexibility is further increased. Can be increased.

The axial length of the cylindrical portion is preferably set to be longer than 1/2 of the outer diameter of the cylindrical portion. Thereby, the function as a guide for the cylindrical processing portion can be more reliably realized.

It is desirable that the axial length of the cylindrical processing portion is set longer than the axial length of the knurling portion. Thereby, the function of restricting the radial direction of the pinion body by the cylindrical processing portion and the cylindrical guide portion can be exhibited well, and even if the knurl processing portion is pressed into the knurl crimping portion with a strong force, the pinion main body is Does not deviate from the shaft center of the joint shaft.

It is desirable that the outer diameter of the cylindrical processing portion is set to be larger than the inner diameter of the cylindrical guide portion of the connecting shaft, that is, set so as to be an interference fit. This allows
It is possible to reliably prevent the cylindrical processing portion of the pinion body from rattling in the cylindrical guide portion, and to secure the radial guiding function for a long time.

Further, of the pair of bearings supporting the joint shaft in the bearing case, the outer diameter of the joint shaft in the portion where the bearing on the head portion side is disposed is the maximum outer diameter of the head portion of the pinion body. It is desirable that the value is set to be larger than the above (claim 6). Thus, after the pinion body is press-fitted into the joint shaft, the bearing can be press-fitted into the joint shaft such that the head portion of the pinion body penetrates the bearing,
Easier assembly is possible.

It is desirable that the outer diameter of the joint shaft near the knurled crimping portion is set to be 1.5 times or more the inner diameter of the knurled crimping portion. As a result, even if the knurled portion and the knurled crimping portion are fixed to each other with a strong interference fit, a joint shaft strength that can provide a reaction force that can withstand the strong joint is obtained. (Torque transmission) can be maintained satisfactorily for a long period of time.

When the structure according to the present invention is applied to a case where a strong torque is not handled, the above-mentioned "bolt screwed into the shaft center of the pinion body through the joint shaft from the drive shaft side" Can be omitted (claim 7). In this case, the fixing of the knurled portion and the knurled crimping portion realizes integration in both the rotation direction and the axial direction.

In the present invention, the nature of the invention is not particularly limited with respect to the type of pinion, that is, the form of the power transmission surface. That is, the present invention is applicable to a pinion used in a general parallel shaft gear mechanism, in addition to a pinion used in an orthogonal gear mechanism such as a bevel pinion or a hypoid pinion. Further, instead of a "gear", a "roller" for transmitting traction may be used, and this case is also included in the scope of the present invention.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing a connecting shaft device for connecting a motor shaft (drive shaft) and a gear on a reduction gear side, to which a pinion mounting structure according to an embodiment of the present invention is applied. 2, 3 show the joint shaft and the pinion body respectively.

FIG. 4 is a longitudinal sectional view showing the structure of a main part of a reduction gear with a motor to which the connecting shaft device is applied.

The joint shaft device 100 is mounted with a joint shaft 104 via a motor shaft (drive shaft: not shown in FIG. 1; see FIG. 4) 102 and a key (see FIG. 4) 103 so as to be integrally rotatable. A basic configuration is adopted in which the pinion main body 106 is mounted on the joint shaft 104 so as to be integrally rotatable.

The pinion body 106 is provided with a next gear 108.
A head portion 112 including a gear cutting portion 110 which meshes with the cylindrical portion, a cylindrical portion 116 formed coaxially with the head portion 112 and having a step 114, and a cylindrical portion 116;
And a knurled portion 118 which is knurled coaxially and slightly smaller in diameter than the cylindrically processed portion (may be continuous with the same size).

The connecting shaft 104 is brought into contact with the step 114 of the pinion main body 106 so that the pinion main body 106
A reference end 120 whose axial position with respect to the joint shaft 104 is determined, and a concave portion 122 into which the cylindrical portion 116 and the knurl portion 118 of the pinion body 106 are inserted. More specifically, the concave portion 122 is formed by the cylindrical guide portion 1 that regulates the radial position of the pinion main body by guiding and inserting the cylindrical processing portion 116 of the pinion main body.
24, and a knurl crimping portion 126 that allows the torque of the connecting shaft 104 to be transmitted to the pinion main body when the knurled portion 118 is press-fitted.

On the other hand, from the motor shaft 102 side, the connecting shaft 10
4, a bolt 130 is screwed into the shaft center of the pinion main body 106 so as to prevent the pinion main body 106 from coming off the joint shaft 104.

Hereinafter, the configuration of each unit will be described in more detail.

The pinion body 106 constitutes a so-called bevel pinion in which a bevel gear 110 is formed in a head portion 112 thereof. This pinion body 10
It is desirable that the axial length LP of the cylindrical processing portion 116 be at least １ ／ or more of the outer diameter DP of the cylindrical processing portion 116. This is because if the axial length LP is too short with respect to the outer diameter DP, the radial position regulation of the pinion main body 106 does not function sufficiently. In the present embodiment, the axial length LP of the cylindrical portion 116 is set to substantially the same dimension as the outer shape DP.

The length LP of the cylindrical portion 116 is set to be longer than the length LR of the knurl portion 118. That is, if this length relationship is reversed,
This is because the guide function of the cylindrical processing portion 116 cannot be sufficiently exhibited, and the axis P0 of the pinion main body 106 and the axis C0 of the joint shaft 104 may be displaced by a strong pressure at the time of knurling (press-fitting). is there.

The outer diameter DP of the cylindrical portion 116 is
It is set slightly larger than the inner diameter dP of the cylindrical guide portion 124 of the connecting shaft 104 (DP> dP), which is a so-called interference fit. This is because there is no gap or play between the cylindrical processing portion 116 of the pinion main body 106 and the cylindrical guide portion 124 of the joint shaft 104 (regardless of tolerance).
And this guide state can be maintained for a long period of time.

The knurled portion 1 of the pinion body 106
Reference numeral 18 is formed by a known knurling process, and is characterized in that fine irregularities (streaks) 118A are formed along the axial direction. This knurl processing section 118
Is pressed into the knurled crimping portion 126 of the joint shaft 104, the knurled crimping portion 126 is
Are plastically deformed by the surface irregularities 118A, and are firmly fixed so as to bite each other. Reference numeral 132 in FIG. 3 is a hole into which the bolt 130 is screwed.

On the other hand, the connecting shaft 104 is provided with the concave portion (continuous one of the cylindrical guide portion 124 and the knurling portion 126) 122 into which the cylindrical portion 116 of the pinion main body 106 is inserted as described above. When the pinion main body 106 is inserted into the concave portion 122, the step portion 114 of the pinion main body 106 comes into contact with the reference end 12, which determines the axial position of the pinion main body 106 with respect to the joint shaft 104.
0 is provided.

Further, a ring-shaped convex portion 104A is formed on the outer periphery of the connecting shaft 104. The ring-shaped convex portion 104A connects the joint shaft 104 to the bearing case (casing) 1.
A pair of bearings 15 for rotatably supporting the bearings 40
0, 152 and the connecting shaft 10
4 is formed in order to secure a large wall thickness in the vicinity of the knurled crimp portion 126. Knurl crimping part 12
It is necessary to secure a large thickness in the vicinity of 6 because the knurled portion 118 of the pinion main body 106 is pressed into the knurled crimping portion 126 of the joint shaft 104 with a strong force to provide a sufficient reaction force. To get Specifically, the outer diameter D of the joint shaft 104 near the knurled crimping portion 126
C is set to be approximately three times the inner diameter dR of the knurled crimping portion 126 due to the presence of the ring-shaped convex portion 104A. In addition, even if sufficient thickness cannot be secured due to space, the connecting shaft 104 near the knurled crimping portion 126 can be used.
Is preferably at least 1.5 times the inner diameter dR of the knurled crimping portion 126.

On the other hand, the bearing case 140 has a locking projection 140A for locking the bearing 150 of the pair of bearings 150 and 152 on the side where the head portion 112 of the pinion body 106 is present. At the end. The bearing 150 is provided between the locking projection 140A and the connecting shaft 104.
Is positioned in the axial direction by being sandwiched between one end side 104A1 of the ring-shaped convex portion 104A.

The end of the bearing case 140 opposite to the side where the locking projections 140A are located is provided with a cover 1.
60 is assembled via bolts 162. The cover body 160 includes a first contact surface 160A that contacts the end 140B of the bearing case 140 and a second contact surface 160B that contacts the bearing 152. This cover body 160 is
Ring-shaped convex portion 104A of contact surface 160B and joint shaft 104
The bearing 152 is held between the bearing case 140 and the other end side 104A2, and is fixed to the bearing case 140 via the first contact surface 160A. Position in the direction. That is, the bearing 150, between the locking projection 140A and the second contact surface 160B,
The joint shaft 104 is axially positioned with respect to the bearing case 140 by sandwiching the convex portion 104 </ b> A and the bearing 152.

Since the pinion main body 106 is positioned in the axial direction with respect to the joint shaft 104 by the contact between the step 114 and the reference end 120, the pinion main body 106 is pivotally moved relative to the bearing case 140 by the above-described configuration. Direction. As shown in FIG. 4, since the distance LL between the bearing case 140 and the next gear 108 is defined, the head unit 1 of the pinion main body 106 has the above configuration.
The gear cutting portion 110 of the gear 12 is a gear cutting portion 108A of the gear 108.
Is accurately positioned with respect to

FIG. 4 shows a state in which the connecting shaft device 100 according to this embodiment is applied between the motor M and the three-stage parallel shaft gear reducer G.

Incidentally, reference numeral 170 in FIGS. 1 and 4 denotes a seal member.

Next, the operation will be described.

When the motor shaft 102 of the motor M rotates,
The joint shaft 104 rotates integrally with this. Pinion body 1
06 rotates integrally with the spliced shaft 104 as it is because its own knurled portion 118 is firmly pressed into the knurled crimping portion of the spliced shaft 104. At this time, connecting shaft 1
04 is supported by the bearing case 140 via the pair of bearings 150 and 152 (in a state of being centered), so that there is almost no vibration during rotation and the pinion body 106
Since the cylindrical part 116 of the joint 104 is guided by the interference fit of the cylindrical guide part 124 of the joint shaft 104, it can rotate in a state of being completely integrated with the joint shaft 104 (without deviation of the axes P0 and C0).

Since a key is not used for connecting the pinion body 106 and the connecting shaft 104, the dimension RK of the bearing case 140 particularly near the gear cutting portion 110 can be reduced. Further, in the conventional example shown in FIG. 5, since the connection is made by the key 16, as shown by the broken line in FIG.
It is inevitable that the lubricating oil on the side enters the motor M side. However, in the present embodiment, the press-fitting in the cylindrical processing portion and the cylindrical guide portion and the knurling in the knurl processing portion and the knurling crimping portion are performed. This problem does not occur because the two 106 and 104 are connected.

Further, each of the pair of bearings 150 and 152 has a locking projection 140A of the bearing case 140 and one end side 104A of the ring-shaped projection 104A of the connecting shaft 104.
1, the other end side 104A2, the axial position is regulated by the second contact surface 160B of the cover body 160, while the cover body 160 is its own first contact surface 160A is the other end of the bearing case 140 Since the position in the axial direction is regulated by abutting on the portion 140B, the bearing case 1
The axial position of the connecting shaft 104 with respect to 40 is accurately defined.

The connecting shaft 104 and the pinion main body 106 are connected to the step 114 of the pinion main body and the reference end 120 of the connecting shaft 104.
And the axial position of the pinion body 106 is determined by the knurled joint at the knurled crimping portion and the fixing from the motor shaft 102 side by the bolt 130.
10 can always mesh with the gear 108 in the correct position. Further, the function of the bolt 130 can assist the knurling, so that it is possible to reduce the press-fitting force of the knurling.

Here, the axial length L of the cylindrical portion 116
P is almost the same as the outer diameter DP of the cylindrical portion 116 (1/2
The length of the pinion main body 1 in the cylindrical guide part 124 of the cylindrical processing part 116 is set to be longer.
The position control in the radial direction of 06 is performed very well.

The axial length L of the cylindrical portion 116
Since P is set to be longer than the axial length LR of the knurled portion 118, the guide function is excellently exhibited, and even if a strong press force is applied at the time of knurling, the shaft center (P0 and C
0) does not shift.

Further, since the outer diameter DP of the cylindrical processing portion 116 is set to be larger than the inner diameter dP of the cylindrical guide portion 124 (so as to be tightly fitted), the guiding function is reliably performed for a long period of time. Can be maintained.

Although the procedure for assembling the connecting shaft device 100 is not particularly limited, in this embodiment, the bearing 1
Since the outer diameter DB of the connecting shaft 104 in the portion where the 50 is disposed is set to be larger than the maximum outer diameter DS of the head portion 112 of the pinion main body 106, the pinion main body 106
Is mounted on the joint shaft 104, and then the bearing 150 is attached to the joint shaft 104.
Can be attached. Therefore, each member can be assembled very easily.

Further, the outer diameter DC of the joint shaft 104 near the knurled crimping portion 126 is about three times (1.5 times or more) the inner diameter dR of the knurled crimping portion 126 by utilizing the presence of the ring-shaped convex portion 104A. ), The pinion body 10 is pressed with strong pressure to perform knurling.
Even if 6 is press-fitted into the concave portion 122 of the connecting shaft 104, a strength that can withstand it can be obtained.

In the above embodiment, the bolt 130 is screwed into the pinion main body 106, but this bolt can be omitted depending on the application. Also, the order of forming the “cylindrical processed portion” and the “knurled processed portion” with respect to the “head portion” may be reversed. That is, they may be formed in the order of “head portion”, “knurled portion”, and “cylindrical portion”.

In the above-described embodiment, the outer diameter DB of the connecting shaft 104 where the bearing 152 is disposed is determined by considering the easiness of assembly in the head 11 of the pinion body 106.
Although the maximum outer diameter DS is set to be larger than 2, the present invention is not particularly limited to this relationship.

The order of assembly is not limited.

Although the configuration of the above embodiment has almost no problem in practical use, if it is necessary to perform the positioning in the axial direction with higher accuracy, the position between the bearing 152 and the cover body 160 may be reduced. Inserting a shim (a thin plate-like component for gap adjustment) (not shown), the cover body 160 is attached to the bearing case 140.
It is good to adjust the gap at the time of contact with both the other end 140B and the bearing 152. This adjustment may be performed by inserting a shim between the first contact surface 160A of the cover body 160 and the other end 140B of the bearing case 140, or may be performed by inserting an shim between the end of the bearing 152 and the cover body 160. May be performed by directly shaving the second contact surface 160B.

[0059]

According to the present invention, it is possible to prevent the leakage of the lubricating oil without applying the sealant, and the design flexibility is high. In particular, in the radial direction of the bearing case near the gear cut portion. An excellent effect of being able to suppress the size of is obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a connecting shaft device to which a pinion mounting structure according to an embodiment of the present invention is applied.

FIG. 2 is an enlarged longitudinal sectional view of a connecting shaft in the embodiment.

FIG. 3 is an enlarged front view of the pinion body and an arrow IIIB.
End view seen from the direction

FIG. 4 is a longitudinal sectional view of a main part of a three-stage gear reducer with a motor to which the above-described connecting shaft device is applied.

FIG. 5 is a longitudinal sectional view showing a conventional pinion mounting structure.

FIG. 6 is a longitudinal sectional view showing another conventional pinion mounting structure.

[Explanation of symbols]

 Reference numeral 102: motor shaft (drive shaft) 104: joint shaft 106: pinion main body 112: head 114: step 116: cylindrical processing part 118: knurl processing part 120: reference end part 122: concave part 124: cylindrical guide part 126: knurl crimping Part 130: Bolt 150, 152: Bearing 160: Cover

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3J030 AC10 BA02 BB03 BB18 BC02 BD02 BD06 3J063 AB04 AC01 BB41 BB50 CB17 CB58 XA02

Claims (8)

[Claims] 1. A pinion mounting structure in which a joint shaft is attached to a tip of a drive shaft so as to be integrally rotatable with the drive shaft, and a pinion body is attached to the joint shaft so as to be integrally rotatable. A head portion including a gear cutting portion that meshes with the gear of the step, a cylindrical processing portion formed in a cylindrical shape coaxially with the head portion, and a knurl processing portion knurled coaxially with the cylindrical processing portion. The joint shaft regulates the radial position of the pinion body by guiding and inserting the cylindrical processing portion, and reduces the torque of the joint shaft by press-fitting the knurled portion. A knurl crimping portion that can be transmitted to the pinion main body, and a bolt is screwed into a shaft center portion of the pinion main body through the joint shaft from the drive shaft side, and the pinion main body is moved from the joint shaft. Escape Mounting structure of the pinion, characterized in that but is prevented. 2. The pinion body according to claim 1, wherein the cylindrical processing portion of the pinion main body is formed in a cylindrical shape coaxial with the head portion and has a step, and the connecting shaft abuts on the step. A pinion mounting structure having a reference end portion at which an axial position of a pinion body with respect to a joint shaft is determined. 3. The cylindrical processing part according to claim 1, wherein an axial length of the cylindrical processing part is one of an outer diameter of the cylindrical processing part.
A pinion mounting structure characterized by being set longer than / 2. 4. The pinion mounting structure according to claim 1, wherein an axial length of the cylindrical processing portion is set to be longer than an axial length of the knurling portion. 5. The pinion mounting structure according to claim 1, wherein an outer diameter of the cylindrical processing portion is set to be larger than an inner diameter of the cylindrical guide portion of the joint shaft. 6. The connecting shaft according to claim 1, wherein the joint shaft is rotatably supported by a bearing case by a pair of bearings, and the bearing on the head portion side of the pair of bearings is disposed. The outer diameter of the connecting shaft at the portion where the pinion is set is larger than the maximum outer diameter of the head portion of the pinion body. 7. The knurled crimping portion according to claim 1, wherein an outer diameter of the joint shaft in the vicinity of the knurled crimping portion is set to be 1.5 times or more an inner diameter of the knurled crimping portion. Pinion mounting structure. 8. A pinion mounting structure in which a joint shaft is attached to a tip of a drive shaft so as to be integrally rotatable with the drive shaft, and a pinion body is attached to the joint shaft so as to be integrally rotatable. A head portion including a gear cutting portion that meshes with the gear of the step, a cylindrical processing portion formed in a cylindrical shape coaxially with the head portion, and a knurl processing portion knurled coaxially with the cylindrical processing portion. The joint shaft comprises a cylindrical guide portion for regulating the radial position of the pinion body by guiding and inserting the cylindrical portion of the pinion body, and the joint shaft by press-fitting the knurled portion. And a knurled crimping portion that transmits the torque of the pinion to the pinion main body and prevents the pinion main body from coming off the joint shaft.