JP7398948B2 - axle case - Google Patents

Description

The present disclosure relates to an axle case.

Shrink fitting is generally used to join the cast iron axle case body and the tube end.

Japanese Patent Application Publication No. 2001-277812

However, in order to ensure joint quality, it is necessary to make the pilot part thicker, which makes the tube end heavier. Furthermore, there is a possibility that the tube end will tilt with respect to the axle case body due to its weight. If the tube end is joined in an inclined state with respect to the axle case body, it will cause a decrease in the static accuracy of the joint.

On the other hand, when joining by friction welding or rotary arc welding is employed, a decrease in the static accuracy of the joint can be suppressed. However, since scale is generated from the joints, the scale falls into the axle case, causing a reduction in the life of the gear.

The present disclosure was devised in view of such circumstances, and an object thereof is to provide an axle case that can suppress falling of scale into the axle case.

According to one aspect of the present disclosure, a cylindrical first joint allowance formed at the tip of the axle case body;
a cylindrical second joint margin formed at the base end of the tube end and coaxially joined to the first joint margin by friction welding or welding;
a fitting part formed on the axle case body and fitted within the second joint allowance;
an axle case comprising: a scale receiving part formed in a groove shape on the outer peripheral surface of the fitting part to receive scale generated when joining the second joining part to the first joining part; provided.

Preferably, the first welding margin and the second welding margin are joined by friction welding, and a welding curl formed on the inner peripheral side of the joined portion is accommodated in the scale receiving portion.

Preferably, the outer circumferential surface of the fitting portion is spaced apart from the inner circumferential surface of the second joint margin by a small distance.

Preferably, the first joining margin and the second joining margin are joined by welding, and the outer circumferential surface of the fitting portion is brought into contact with the inner peripheral surface of the second joining margin.

According to the above aspect, it is possible to suppress the scale from falling into the axle case.

FIG. 2 is a rear view of an axle case according to an embodiment of the present disclosure. FIG. 3 is a sectional view of main parts of the axle case. FIG. 3 is a sectional view of main parts of the axle case body. It is a sectional view of a tube end. FIG. 3 is a cross-sectional view of a main part of the tube end in a state where the tube end is frictionally welded to the axle case body.

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. In addition, each direction of front, rear, left, right, top and bottom in the embodiment described later shall refer to each direction of the vehicle. However, each direction in this embodiment is used for convenience of explanation, and represents a relative positional relationship between members to be described later.

FIG. 1 is a rear view of the axle case. FIG. 2 is a sectional view of the right end portion of the axle case.

As shown in FIGS. 1 and 2, the axle case 1 includes an axle case body 2 extending in the left-right direction, and a tube end 3 joined to the left and right tips of the axle case body 2 by friction welding.

The axle case body 2 is made of cast iron. The axle case body 2 includes a housing portion 4 in which a final gear (not shown) is housed, and an axle tube portion 5 extending from the housing portion 4 to both left and right sides. The axle tube portion 5 is formed into a cylindrical shape and rotatably accommodates an axle shaft (not shown). The axle case 1 is formed generally symmetrically. Therefore, in the following description of the end structure of the axle case 1, the right end part of the axle case 1 will be described, and the description of the left end part of the axle case 1 will be omitted.

As shown in FIGS. 2 and 3, a first joining margin 6 for joining to the tube end 3 is formed at the tip (right end) of the axle tube portion 5. The first joint allowance 6 is formed into a cylindrical shape. The inner diameter a and the outer diameter b of the first joint allowance 6 are formed to be constant in the axial direction.

As shown in FIGS. 2 and 4, the tube end 3 is made of steel and has a cylindrical shape. Note that the material of the tube end 3 is not limited to this. The material of the tube end 3 may be other metals that can be frictionally welded to the axle case body 2. A second joining margin 9 is formed at the base end (left end) of the tube end 3 to be joined to the distal end portion of the axle tube portion 5, that is, the first joining margin 6. The second joint allowance 9 is formed in a cylindrical shape. The inner diameter c of the second joint allowance 9 is set to be the same as the inner diameter a of the first joint allowance 6 (inner diameter c = inner diameter a), and the outer diameter d of the second joint allowance 9 is the outer diameter of the first joint allowance 6. b (inner diameter d=inner diameter b).

Further, a first shaft insertion hole 3a through which the axle shaft is rotatably inserted is formed in the tube end 3 on the distal side (right side) of the second joint allowance 9. The diameter e of the first shaft insertion hole 3a is set smaller than the inner diameter c of the second joint allowance 9. Furthermore, a stepped surface 3c is formed between the inner circumferential surface 3b of the tube end 3 in the portion that partitions the first shaft insertion hole 3a and the inner circumferential surface 9a of the second joining margin 9, which connects them. The stepped surface 3c is formed in a planar shape perpendicular to the central axis P of the tube end 3.

By the way, when joining the first joining allowance 6 and the second joining allowance 9 by friction welding, there is an upper limit to the thickness f of the first joining allowance 6 and the thickness g of the second joining allowance 9. For this reason, when the required strength is high, the strength of the first joint allowance 6 and the second joint allowance 9 may be insufficient. In addition, scale is generated when the second welding margin 9 is joined to the first welding margin 6 by friction welding. Therefore, the scale may fall into the axle case 1, which may cause a reduction in the life of the gear.

Therefore, the axle case 1 in this embodiment includes a fitting part 10 that fits into the second joint allowance 9, and a scale receiving part 11 that is formed in a groove shape on the outer peripheral surface 10c of the fitting part 10 and receives the scale. Equipped with.

As shown in FIGS. 2 and 3, the fitting portion 10 and the first joining portion 6 are integrally formed in the axle case body 2. As shown in FIGS. The fitting part 10 is formed in a cylindrical shape. The outer diameter x of the fitting part 10 is set smaller than the inner diameter a of the first joining allowance 6, and the fitting part 10 is arranged coaxially with the first joining allowance 6. That is, the first joint allowance 6 and the fitting portion 10 are arranged in a double cylindrical shape. Further, the base end (left end) of the fitting portion 10 is connected to the base end (left end) of the first joining margin 6. The distal end (right end) of the fitting portion 10 projects axially outward (rightward) from the first joint allowance 6 . The outer diameter x of the fitting portion 10 is set so that the fitting portion 10 is fitted into the second joint allowance 9 with a small interval therebetween. That is, the outer diameter x of the fitting part 10 is set smaller than the inner diameter c of the second joining allowance 9, and the outer peripheral surface 10c of the fitting part 10 is spaced apart from the inner peripheral surface 9a of the second joining allowance 9 by a small distance. separated from each other. This prevents the fitting portion 10 from coming into frictional contact with the second joining margin 9 when the first joining margin 6 and the second joining margin 9 are frictionally welded.

Furthermore, a second shaft insertion hole 10a is formed in the fitting portion 10, through which the axle shaft is rotatably inserted. The diameter y of the second shaft insertion hole 10a is set to be approximately the same as the diameter e of the first shaft insertion hole 3a (diameter y=diameter e). Note that the diameter y of the second shaft insertion hole 10a may be set larger than the diameter e of the first shaft insertion hole 3a (diameter y>diameter e). The distal end surface 10b of the fitting portion 10 is axially spaced apart from the step surface 3c with a small gap in the state where the first joining portion 6 and the second joining portion 9 are joined as shown in FIG. It is formed by adjusting the position of the direction. As a result, when the first welding allowance 6 and the second joining allowance 9 are friction-welded, the distal end surface 10b of the fitting portion 10 and the stepped surface 3c come into contact with each other, thereby inhibiting movement of the axle case body 2 in the axial direction. things are suppressed.

The scale receiving portion 11 is formed in the outer peripheral surface 10c of the fitting portion 10 in the shape of a groove having a U-shaped cross section. The scale receiving part 11 is formed in an annular shape around the entire circumference of the outer peripheral surface 10c of the fitting part 10. The scale receiving portion 11 is formed by forming inner welding curls 12a and 12b formed on the outer circumferential side and the inner circumferential side of the welded portion when the first welding allowance 6 and the second welding allowance 9 are friction welded. It has a function of accommodating the circumferential pressing curl 12b.

The left-right dimension (dimension in the groove width direction) α of the scale receiving portion 11 is set to be larger than the left-right dimension w of the pressure contact curl 12b on the inner peripheral side. Further, the scale receiving portion 11 is formed so that the pressing curl 12b is located at the center in the left-right direction. Specifically, the position of the scale receiving part 11 in the left-right direction is determined in accordance with the position of the press-contact curl 12b in the left-right direction estimated in advance through experiments, simulations, or the like. Further, the groove depth β of the scale receiving portion 11 is set to be larger than the radially inward protrusion amount t of the pressure welding curl 12b. As a result, the scale receiving portion 11 covers the entire press-contact curl 12b from the inner circumferential side and receives the scale peeled off from the press-contact curl 12b.

Next, the operation of this embodiment will be described.

When joining the tube end 3 to the axle case body 2 by friction welding, the axle case body 2 and the tube end 3 are coaxially connected so that the first joining allowance 6 and the second joining allowance 9 face each other with an interval in the axial direction. Place it in Thereafter, as shown in FIG. 5, for example, the axle case body 2 is moved to approach the tube end 3 while rotating the tube end 3 around the central axis of the second joint allowance 9, and The first welding allowance 6 is pressed against. As a result, the first welding margin 6 and the second welding margin 9 are brought into frictional contact with each other and generate heat. Although the tube end 3 is rotated and the axle case body 2 is moved toward the tube end 3, the present invention is not limited thereto. Conversely, the tube end 3 may be moved toward the axle case body 2 by rotating the axle case body 2.

Thereafter, when the first welding allowance 6 and the second joining allowance 9 reach a predetermined temperature, the rotation of the tube end 3 is rapidly stopped and the pressure with which the axle case body 2 is pressed against the tube end 3 is increased to a predetermined pressure. Here, the predetermined temperature is a temperature suitable for bonding, and is set in advance. Further, the predetermined temperature is estimated based on the contact area, contact time, and pressure between the first joining portion 6 and the second joining portion 9. That is, in actual control, the timing to stop the tube end 3 is determined based on the contact area, contact time, and pressure between the first joining margin 6 and the second joining margin 9. Further, the predetermined pressure is a pressure suitable for bonding (upset pressure) and is set in advance.

By maintaining this state for a predetermined time (upset time), pressure welding curls 12a and 12b are formed on the first joining allowance 6 and the second joining allowance 9, and the first joining allowance 6 and the second joining allowance 9 are integrated. Joined. At this time, scale (not shown) may come off from the pressure curls 12a and 12b. However, the pressure curl 12b on the inner peripheral side is surrounded by the scale receiving portion 11. Therefore, the scale peeled off from the inner pressure curl 12b is trapped within the scale receiving portion 11. Therefore, scale can be prevented from entering the first shaft insertion hole 3a and the second shaft insertion hole 10a.

Further, since the axle case body 2 and the tube end 3 are joined by friction welding, deterioration in static accuracy can be suppressed more than when joining by shrink fitting. Further, the axle case body 2 can be made of inexpensive cast iron.

In addition, in joining by friction welding, there is an upper limit to the thickness of the first joining allowance 6 and the second joining allowance 9, and the bending strength of the first joining allowance 6 and the second joining allowance 9 that constitute the joint part may be insufficient. There is sex. When a load in the bending direction is applied to the first joint allowance 6 and the second joint allowance 9, there is a possibility that the first joint allowance 6 and the second joint allowance 9 are bent by the load. However, when the first joining allowance 6 and the second joining allowance 9 are bent, the fitting portion 10 hits the inner circumferential surface 9a of the second joining allowance 9. Thereby, the first joining allowance 6 and the second joining allowance 9 are supported by the fitting portion 10, and the bending strength of the first joining allowance 6 and the second joining allowance 9, that is, the joint portion can be increased.

Although the embodiments of the present disclosure have been described in detail above, other embodiments of the present disclosure as described below are also possible.

(1) Although the first joining portion 6 and the second joining portion 9 are joined by friction welding, the present invention is not limited to this. For example, the first joining margin 6 and the second joining margin 9 may be joined by welding such as rotary arc welding. In this case, the axle case body 2 and tube end 3 are preferably made of a metal with excellent weldability, such as steel or cast steel. Furthermore, the fitting portion 10 may be fitted into the second joint portion 9 with its outer circumferential surface 10c in contact with the inner peripheral surface 9a of the second joint portion 9. When welding the first joining margin 6 and the second joining margin 9, the first joining margin 6 and the second joining margin 9 can be kept coaxial, and can be joined easily and accurately. Moreover, in this case, the scale receiving part 11 is preferably arranged adjacent to the inner peripheral side of the welding position. The weld bead on the inner peripheral side can be accommodated in the scale receiving part 11, and the scale that comes off from the welding bead can be confined in the scale receiving part 11. In addition, scale can be prevented from entering the first shaft insertion hole 3a and the second shaft insertion hole 10a.

(2) Although the scale receiving portion 11 is formed in the shape of a groove having a U-shaped cross section on the outer circumferential surface 10c of the fitting portion 10, the scale receiving portion 11 is not limited thereto. For example, the groove shape of the scale receiving portion 11 may have an arcuate cross section.

1: Axle case 2: Axle case body 3: Tube end 6: First joint allowance 9: Second joint allowance 9a: Inner peripheral surface 10: Fitting portion 10a: Second shaft insertion hole 11: Scale receiving portion 12a: Pressure welding Curl 12b: Pressure curl

Claims (1)

a cylindrical first joint allowance formed at the tip of the axle case body;
a cylindrical second joint margin formed at the base end of the tube end , abutted against the first joint margin, and coaxially joined by friction welding ;
a fitting part formed on the axle case body and fitted within the second joint allowance;
a scale receiving part formed in a groove shape extending all the way around the outer peripheral surface of the fitting part to receive scale generated when joining the second joining part to the first joining part ,
The inner diameter and outer diameter of the second joint allowance are set to be the same as the inner diameter and outer diameter of the first joint allowance,
The fitting portion has an outer diameter smaller than the inner diameter of the second joint allowance, and is protruded further toward the distal end than the first joint allowance,
The outer circumferential surface of the fitting portion is spaced apart from the inner circumferential surface of the second joint margin by a small distance,
The scale receiving portion is configured to accommodate a pressure welding curl formed on the inner circumferential side when the first welding margin and the second welding margin are friction welded, and the scale receiving portion is configured to accommodate a pressure welding curl formed on the inner peripheral side when the first welding margin and the second welding margin are friction welded, and the scale receiving portion is configured to accommodate a welding curl formed on the inner circumferential side when the first welding margin and the second welding margin are friction welded. It is formed from a position on the proximal side to a position on the distal side,
A dimension of the scale receiving portion in the groove width direction is larger than a dimension of the pressure-welding curl in the groove width direction,
The scale receiving part is formed so that the pressure curl is located at the center in the width direction of the scale, and the pressure curl is not brought into contact with the proximal and distal end surfaces of the scale receiving part,
The groove depth of the scale receiving portion is set to be larger than the amount of radial inward protrusion of the pressure welding curl so as to prevent the pressure welding curl from coming into contact with the bottom surface of the groove of the scale receiving portion.
The axle case is characterized by:

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