De Dion axle structure

Abstract

To provide a de Dion axle structure capable of increasing attachability / detachability of a drive shaft and increasing strength by preventing application of a return input to a de Dion tube.SOLUTION: This de Dion axle structure comprises: a de Dion tube 2 extending in a vehicle width direction; suspension attachments 3 provided at both ends of the de Dion tube 2; a pair of drive shafts 6 extending from a power source 5 mounted on a vehicle body frame 4 to the suspension attachments 3; and a pair of output shafts 7 rotated by the drive shafts 6. Input gears 15 rotated by the drive shafts 6 and output gears 16 engaged with the input gears 15 to be offset behind the input gears 15 are stored in the suspension attachments 3. The output shafts 7 are connected to the output gears 16. The output shafts 7 are offset behind the drive shafts 6. The de Dion tube 2 is formed into a straight shape.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a de Dion axle structure used for the drive wheels of vehicles such as trucks and buses, and in particular to a de Dion axle structure that improves maintainability by improving the ease of removal and installation of the drive shaft, and also improves strength and rigidity by preventing torsional input from being applied to the de Dion tube. [Background technology]

[0002] FIG. 1 shows a perspective view of a conventional de Dion axle structure 1J mounted on a vehicle such as a truck or bus, and FIG. 2 shows a schematic perspective view of the conventional de Dion axle structure 1J. The de Dion axle structure 1J includes a de Dion tube 2J extending in the vehicle width direction, suspension mounting portions 3J provided at both ends of the de Dion tube 2J, a pair of drive shafts 6J extending from a power source (motor unit, engine, differential mechanism, etc.) 5 mounted on a body frame 4 to the left and right suspension mounting portions in the vehicle width direction, and a pair of output shafts 7J rotated by the drive shafts 6J and extending outward in the vehicle width direction from the suspension mounting portions 3J. The suspension mounting portions 3J are fitted with, for example, the middle portions of leaf springs 8 as suspension devices, and both ends of the leaf springs 8 are attached to side rails 4a that form the body frame 4. The de Dion tube 2J connecting the left and right suspension mounting portions 3J is curved rearward to avoid interference with the power source 5 (see Patent Document 1).

[0003] Figure 3 shows a plan cross-sectional view of a conventional De Dion axle structure 1J viewed from above. A constant velocity joint 9J is interposed between a drive shaft 6J and an output shaft 7J. The constant velocity joint 9J is a coupling that transmits rotational force by freely changing the angle between the input drive shaft 6J and the output shaft 7J while maintaining the speeds of both shafts. A portion of the constant velocity joint 9J is housed inside the suspension mounting portion 3J, and a boot (constant velocity joint boot, not shown) is attached to the exposed portion. A spindle 10J is provided in the suspension mounting portion 3J facing outward in the vehicle width direction, and a hub 12 is rotatably attached to the spindle 10J via a bearing 11. The end of the output shaft 7J is non-rotatably attached to the hub 12, and a wheel 13 and a tire 14 are also attached to the hub 12. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-10947 Summary of the Invention [Problem to be solved by the invention]

[0005] As shown in Figure 3, in the conventional De Dion axle structure 1J, the drive shaft 6J and the output shaft 7J are connected in series via a constant velocity joint 9J. Therefore, when performing maintenance and inspection of the drive shaft 7J, the output shaft 7J portion of the long assembly shaft 20J, which integrates the drive shaft 7J, constant velocity joint 9J, and output shaft 7J, must be pulled out inward in the vehicle width direction from the suspension mounting portion 3J, resulting in a problem of poor maintainability.

[0006] For example, during vehicle inspections, the drive shaft 6J must be removed from the suspension mounting portion 3J for inspection and maintenance, and then reassembled. However, because the drive shaft 6J is connected in series to the output shaft 7J via the constant velocity joint 9J, it is extremely difficult to remove the drive shaft 6J alone. Furthermore, once removed, it is also difficult to reinstall, creating maintenance issues. Additionally, because the drive shaft 6J cannot be easily removed, it is also difficult to grease the constant velocity joint 9J during vehicle inspections.

[0007] 3, it is preferable to reduce the operating angle between the drive shaft 6J and the output shaft 7J at the constant velocity joint 9J to reduce the torque loss rate, and in many cases the drive shaft 6J and the output shaft 7J are arranged as closely to a straight line as possible to minimize the offset between the drive shaft 6J and the output shaft 7J in the fore-and-aft direction. As a result, as shown in Figures 1 and 2, the de Dion tube 2J is curved rearward to prevent interference with the drive source 5 (see Patent Document 1).

[0008] However, if the de Dion tube 2J is curved, as shown in Figure 2, the vehicle weight (arrow W) applied to the left and right suspension mounting parts 3J during driving and the road reaction force (arrow R) applied from the left and right tires 14 to the spindle 10J are transmitted via the curved de Dion tube 2J, resulting in a torsional input being applied to the de Dion tube 2J. Therefore, in order to keep the alignment fluctuations of the left and right wheels 13 during driving within a specified range, the curved de Dion tube 2J needs to have a strong structure, which results in increased costs and weight.

[0009] Furthermore, the De Dion tube 2J must be manufactured with high precision because it determines the position and posture (alignment) of the left and right wheels 13 relative to the body frame 4. Here, manufacturing a curved De Dion tube 2J with such precision that the alignment of the left and right wheels 13 falls within a predetermined tolerance requires more production steps than a straight De Dion tube 2 (see FIG. 4), resulting in increased costs.

[0010] The object of the present invention, which was devised in consideration of the above circumstances, is to provide a De Dion axle structure that improves the ease of removal and installation of the drive shaft, thereby improving maintainability, and that prevents torsional input from being applied to the De Dion tube, thereby improving strength and rigidity. [Means for solving the problem]

[0011] According to the present invention, which has been devised to achieve the above object, there is provided a de Dion axle structure comprising a de Dion tube extending in the vehicle width direction, suspension mounting portions provided at both ends of the de Dion tube, a pair of drive shafts extending from a power source mounted on the vehicle frame to the suspension mounting portions, and a pair of output shafts rotated by the drive shafts and extending outward in the vehicle width direction from the suspension mounting portions, wherein an input gear rotated by the drive shafts and an output gear meshing with the input gear and offset in the front-to-rear or up-and-down direction of the vehicle body relative to the input gear are housed inside the suspension mounting portions, and the output shafts are connected to the output gears, and the output shafts are offset in the front-to-rear or up-and-down direction of the vehicle body relative to the drive shafts, so that the de Dion tube has a straight shape that does not interfere with the power source. A cover that covers the portion that houses the input gear is removably attached to the suspension mounting portion, and when the cover is removed, the input gear and the drive shaft are removably exposed from the suspension mounting portion. A De Dion axle structure is provided, characterized in that:

[0012] In the De Dion axle structure according to the present invention, A constant velocity joint is interposed between the drive shaft and the input gear, and at least a part of the constant velocity joint is housed inside the suspension mounting part, so that when the cover is removed, the constant velocity joint is exposed so that it can be greased. It may be so.

[0013] In the De Dion axle structure according to the present invention, The suspension mounting portion is provided with a suspension mounting seat for mounting a suspension device, and the suspension mounting seat is disposed vertically above the output gear and output shaft. It's fine. [Effects of the Invention]

[0014] The De Dion axle structure according to the present invention can provide the following effects. (1) Inside the suspension mounting section, the input gear rotated by the drive shaft and the output gear attached to the output shaft are meshed, so by disengaging the gears, the drive shaft can be separated and removed from the output shaft. This improves the ease of removal and installation of the drive shaft, and improves maintainability. (2) The input gear housed inside the left and right suspension mounting parts and the output gear that meshes with it are offset either forward or backward or up and down on the vehicle body, and the drive shaft that rotates the input gear and the output shaft attached to the output gear are also offset either forward or backward or up and down on the vehicle body, so that the De Dion tube connecting the left and right suspension mounting parts has a straight shape that does not interfere with the power source.As a result, when driving, the vehicle weight applied to the left and right suspension mounting parts and the road reaction forces from the left and right tires are transmitted via the straight De Dion tube, and compared to the conventional curved De Dion tube (see Figures 2 and 3), there is no torsional input to the De Dion tube, which is advantageous in terms of strength and rigidity and can promote weight reduction. (3) When manufacturing straight De Dion tubes with high precision to ensure that the left and right wheel alignment is within a specified tolerance, the number of production steps is reduced compared to conventional curved De Dion tubes, allowing for lower manufacturing costs. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a perspective view of a conventional De Dion axle structure attached to a vehicle such as a truck or bus. [Figure 2] FIG. 1 is a perspective view showing an outline of a conventional De Dion axle structure. [Figure 3] FIG. 1 is a cross-sectional plan view of a conventional De Dion axle structure, viewed from above. [Figure 4] 1 is a plan cross-sectional view of a De Dion axle structure according to one embodiment of the present invention, viewed from above. [Figure 5] 1 is a perspective view showing an outline of a De Dion axle structure according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0017] (De Dion Axle Structure 1 Overview) A de Dion axle structure 1 according to one embodiment of the present invention will be described using Figures 4 and 5. The de Dion axle structure 1 according to this embodiment comprises a de Dion tube 2 extending in the vehicle width direction, suspension mounting portions 3 provided at both ends of the de Dion tube 2, a pair of drive shafts 6 extending from a power source (motor unit, engine, differential mechanism, etc.) 5 mounted on a body frame 4 (see Figure 1) to the suspension mounting portion 3, and a pair of output shafts 7 rotated by the drive shafts 6 and extending outward in the vehicle width direction from the suspension mounting portion 3.

[0018] As shown in Figures 4 and 5, an input gear 15 rotated by a drive shaft 6 and an output gear 16 meshing with the input gear 15 are housed inside the suspension mounting part 3. The input gear 15 and the output gear 16 have shafts 18 and 7, respectively, that extend along the vehicle width direction, and these shafts 18 and 7 are rotatably supported inside the suspension mounting part 3 via bearings (not shown). The output gear 16 is offset rearward from the input gear 15, and the output shaft 7 connected to the output gear 16 is offset rearward from the drive shaft 6. This offset allows the De Dion tube 2 connecting the left and right suspension mounting parts 3 to be straight while avoiding interference with the power source 5. Each component will be described below.

[0019] (De Dion Tube 2) As shown in Figures 4 and 5, a straight de Dion tube 2 is bridged between the left and right suspension mounting portions 3 while avoiding interference with the power source 5. In this embodiment, the de Dion tube 2 is formed in a rectangular tube shape, but it may also be cylindrical. In the conventional de Dion tube structure 1J shown in Figure 3, the drive shaft 6J and the output shaft 7J are arranged in a straight line, so the de Dion tube 2J had to be curved toward the rear of the vehicle body to avoid interference with the power source 5. However, in the de Dion tube structure 1 of this embodiment shown in Figure 4, the output shaft 7 is offset rearward relative to the drive shaft 6, so interference with the power source 5 can be avoided even if the de Dion tube 2 is straight.

[0020] (Suspension mounting part 3) As shown in Figures 4 and 5, suspension mounting portions 3 are provided at both ends of a straight De Dion tube 2. A spindle 10 is provided on the suspension mounting portion 3 facing outward in the vehicle width direction, and a hub 12 is rotatably mounted on the spindle 10 via a bearing 11. The tip of an output shaft 7, which is rotatably supported inside the spindle 10, is non-rotatably mounted on the hub 12, and a wheel 13 and a tire 14 are also attached to the hub 12. With this configuration, the road reaction force received by the tire 14 shown in Figure 4 is applied to the spindle 10 via the wheel 13, hub 12, and bearing 11, and acts as a force pushing the output shaft 7 upward (vertically upward) as shown by arrow R in Figure 5.

[0021] As shown in Figures 4 and 5, the suspension mounting section 3 is made up of a front suspension mounting section 3a that houses the input gear 15 and a rear suspension mounting section 3b that houses the output gear 16, with a suspension mounting seat 17 provided above the rear suspension mounting section 3b. To the suspension mounting seat 17, a suspension device such as a leaf spring 8 is attached, for example, as shown in Figure 1, at the middle portion thereof. The leaf spring 8 has both ends attached to side rails 4a of the body frame 4. With this configuration, the vehicle weight acting on the leaf spring 8 is applied to the suspension mounting seat 17 of the suspension mounting section 3 as shown by arrow W in Figure 5, and by positioning the suspension mounting seat 17 vertically above the output gear 16 and output shaft 7, it acts as a force that pushes the output shaft 7 downward (vertically downward).

[0022] (Constant velocity joint 9) As shown in Figure 4, a constant velocity joint 9 is interposed between the drive shaft 6 and the shaft 18 attached to the input gear 15. The constant velocity joint 9 is a joint that transmits rotational force by freely changing the angle between the drive shaft 6 and the shaft 18 attached to the input gear 15 while maintaining the speeds of both. A portion of the constant velocity joint 6 is housed inside the suspension mounting portion 3, and a boot (constant velocity joint boot) (not shown) is attached to the exposed portion. The constant velocity joint 9 can reduce the torque loss rate by reducing the operating angle between the drive shaft 6 and the shaft 18 attached to the input gear 15, and in this embodiment, both shafts 6, 18 are arranged in a straight line in a plan view.

[0023] (Cover 19) As shown in Figure 5, a cover 19 that covers the portion of the suspension mounting part 3 that houses the input gear 15 is removably attached to the suspension mounting part 3. More specifically, the cover 19 is removably attached to the lower part of the front suspension mounting part 3a that houses the input gear 15, and when the cover 19 is removed, the constant velocity joint 9 is exposed so that it can be greased. Furthermore, after the cover 19 is removed, the input gear 15 is disengaged from the output gear 16, so that the input gear 15, the shaft 18 of the input gear 15, the constant velocity joint 9, and the drive shaft 6 are removably exposed downward from the suspension mounting part 3.

[0024] (Actions and Effects) As shown in Figure 4, according to the De Dion axle structure 1 of this embodiment, the input gear 15 rotated by the drive shaft 6 and the output gear 16 attached to the output shaft 7 are meshed inside the suspension mounting portion 3. Therefore, as shown in Figure 5, by disengaging this meshing, the drive shaft 6 can be separated and removed from the output shaft 7, which improves the ease of removal and installation of the drive shaft 6 and improves maintainability.

[0025] More specifically, as shown in Figure 5, removing cover 19 exposes the portion of constant velocity joint 9 covered by a boot (not shown) downward so that it can be greased. This allows the constant velocity joint 9 to be easily greased during vehicle inspections, etc., improving maintainability. Furthermore, after cover 19 is removed, the input gear 15 is disengaged from the output gear 16, allowing the input gear 15, its shaft 18, constant velocity joint 9, and drive shaft 6 to be removed downward as assembly shaft 20, facilitating disassembly and maintenance of the drive shaft 6 and constant velocity joint 9.

[0026] Because the de Dion axle structure 1 determines the mounting positions (alignment) of the left and right wheels 13 relative to the body frame 4 (see Figure 1), high assembly precision is required to ensure proper vehicle posture and driving performance. In the conventional de Dion axle structure 1J shown in Figure 3, the drive shaft 6J, constant velocity joint 9J, and output shaft 7J are connected in a straight line to form an assembly shaft 20J, which has a long overall length. Therefore, the de Dion tube 2J must be disassembled and separated into, for example, the left and right components before the assembly shaft 20J can be removed from the suspension mounting portion 3. However, if a disassembled de Dion tube 2J is reassembled, errors are likely to occur, making it impossible to achieve high assembly precision, and it is possible that the alignment of the left and right wheels 13 may deviate from the specified range.

[0027] In contrast, with the De Dion axle structure 1 according to this embodiment shown in FIG. 4, as shown in FIG. 5, by removing the cover 19 from the suspension mounting portion 3, the assembly shaft 20, which is made up of the drive shaft 6, constant velocity joint 9, shaft 18 of the input gear 15, and input gear 15, can be easily removed from the suspension mounting portion 3 without removing the output shaft 7, without the need to disassemble the De Dion tube 2, suspension mounting portion 3, or spindle 10. Therefore, even when the assembly shaft 20, including the drive shaft 6 and constant velocity joint 9, is removed, the assembly precision of the De Dion tube 2, suspension mounting portion 3, and spindle 10 is maintained at the time of manufacture. As a result, the alignment of the left and right wheels 13 mounted on the spindle 10 shown in FIG. 4 via bearings 11 and hubs 12 does not change when the assembly shaft 20 is attached or detached, and is maintained within the specified range at the time of manufacture.

[0028] Furthermore, as shown in Figure 5, the de Dion tube 2 connecting the left and right suspension mounting parts 3 has a straight shape, so that when driving, the vehicle weight (arrow W) applied to the left and right suspension mounting parts 3 and the road reaction force (arrow R) applied from the left and right tires 14 to the spindle 10 are transmitted via the straight de Dion tube 2. Compared to the conventional curved de Dion tube 2J shown in Figures 2 and 3, there is no torsional input to the de Dion tube 2, which is advantageous in terms of strength and rigidity and can promote weight reduction.

[0029] That is, as shown in Figure 4, the input gear 15 housed inside the left and right suspension mounting parts 3 and the output gear 16 that meshes with it are offset forward and backward on the vehicle body, and the drive shaft 6 that rotates the input gear 15 and the output shaft 7 attached to the output gear 16 are also offset forward and backward on the vehicle body, so that the de Dion tube 2 connecting the left and right suspension mounting parts 3 has a straight shape that does not interfere with the power source 5. For this reason, as shown in Figure 5, the road reaction force (arrow R) applied to the left and right spindles 10 and the vehicle weight (arrow W) applied to the left and right suspension mounting parts 3 are transmitted via the straight de Dion tube 2, eliminating torsional input to the de Dion tube 2 and providing advantages in terms of strength and rigidity.

[0030] More specifically, the road reaction force received by the tire 14 shown in FIG. 4 is applied to the spindle 10 via the wheel 13, hub 12, and bearing 11, and acts as a force pushing the output shaft 7 vertically upward, as shown by arrow R in FIG. 5. On the other hand, the vehicle weight applied to the leaf spring 8 shown in FIG. 1 is applied to the suspension mounting seat 17 of the suspension mounting portion 3, as shown by arrow W in FIG. 5. By locating the suspension mounting seat 17 vertically above the center line of the output gear 16 and output shaft 7, the vehicle weight acts as a force pushing the output shaft 7 vertically downward. Therefore, as shown in FIG. 4, by aligning the center line of the de Dion tube 2 with the extension of the output shaft 7 when viewed from above, the road reaction force pushing the output shaft 7 upward (arrow R) and the vehicle weight pushing the output shaft 7 downward (arrow W) are transmitted along the center line of the de Dion tube 2 when viewed from above, and no torsional input is applied to the de Dion tube 2. This provides advantages in terms of strength and rigidity, and contributes to weight reduction.

[0031] Furthermore, when the straight-shaped De Dion tube 2 shown in Figures 4 and 5 is manufactured with high precision so that the alignment of the left and right wheels 13 is within a specified tolerance, the number of production steps is reduced compared to the conventional curved De Dion tube 2J shown in Figures 2 and 3, and it can be manufactured at low cost.

[0032] The above describes a preferred embodiment of the present invention with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to the above-described embodiment, and various modified or altered examples within the scope of the claims also fall within the technical scope of the present invention.

[0033] For example, in Figures 4 and 5, the output gear 16 may be offset downward (or diagonally rearward and downward) relative to the input gear 15, and the output shaft 7 may be offset downward (or diagonally rearward and downward) relative to the drive shaft 6, and this offset may give the de Dion tube 2 a straight shape that does not interfere with the power source 5.

[0034] In addition, the number of teeth of the output gear 16 may be made greater than the number of teeth of the input gear 15 shown in Figures 4 and 5 to obtain a deceleration effect (reduction effect), or the number of teeth of the input gear 15 may be made greater than the number of teeth of the output gear 16 to obtain a speed-up effect. [Industrial Applicability]

[0035] The present invention can be used in a De Dion axle structure 1 used for the drive wheels of vehicles such as trucks and buses, which improves the ease of removal and installation of the drive shaft 6, thereby improving maintainability, and which prevents torsional input from being applied to the De Dion tube 2, thereby improving strength and rigidity. [Explanation of symbols]

[0036] 1 De Dion axle structure 2 De Dion Tube 3 Suspension mounting part 4 Body frame 4a Side rail 5 Power source 6 drive shaft 7 Output shaft 9 Constant velocity joint 15 Input gear 16 Output gear 19 Cover

Claims

1. A De Dion axle structure comprising: a De Dion tube extending in a vehicle width direction; suspension mounting portions provided at both ends of the De Dion tube; a pair of drive shafts extending from a power source mounted on a vehicle body frame to the suspension mounting portions; and a pair of output shafts rotated by the drive shafts and extending outward in the vehicle width direction from the suspension mounting portions, an input gear rotated by the drive shaft and an output gear meshing with the input gear and offset in the front-to-rear or up-and-down direction of the vehicle body relative to the input gear are housed inside the suspension mounting portion, the output gear is connected to the output shaft, and the output shaft is offset in the front-to-rear or up-and-down direction of the vehicle body relative to the drive shaft, and the De Dion tube has a straight shape that does not interfere with the power source, A De Dion axle structure characterized in that a cover that covers the portion that houses the input gear is removably attached to the suspension mounting portion, and when the cover is removed, the input gear and the drive shaft are removably exposed from the suspension mounting portion.

2. 2. The De Dion axle structure according to claim 1, wherein a constant velocity joint is interposed between the drive shaft and the input gear, at least a portion of the constant velocity joint is housed inside the suspension mounting portion, and when the cover is removed, the constant velocity joint is exposed so that it can be greased.

3. A De Dion axle structure as described in claim 1 or 2, characterized in that the suspension mounting portion is provided with a suspension mounting seat for mounting a suspension device, and the suspension mounting seat is positioned vertically above the output gear and the output shaft.

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