Connection structure between power transmission shafts for vehicle

Abstract

The utility model provides a connecting structure between power transmission shafts for a vehicle. The connecting structure does not need to increase parts or improve the precision of the parts, can restrain the bending of the shafts at an embedding part, and also can ensure the assembling and disassembling performance. In the spline fitting (spline fitting part (54)) of the C shaft (52) and the FD shaft (56), the rear end of the insertion direction of the top surface (54a1) of the outer diameter side spline teeth (54a) and the rear end of the insertion direction of the top surface (54b1) of the inner diameter side spline teeth (54b) are provided with platform-shaped convex parts (54a2, 54b2) for reducing the gap during the fitting, or the convex parts (54a2, 54b2) are provided at the rear end of the insertion direction of the top surface (54a1) of the outer diameter side spline teeth (54a) and the rear end of the insertion direction of the top surface (54b1) of the inner diameter side spline teeth (54b). Table-shaped protrusions (54a3, 54b3) are provided at the tip in the insertion direction of the top surface (54a1) of the outer-diameter-side spline teeth (54a) and at the tip in the insertion direction of the top surface (54b1) of the inner-diameter-side spline teeth (54b), said protrusions (54a3, 54b3) reducing gaps during fitting. As a result, a gap between both ends of the spline fitting part (54) is reduced, and deflection of the C shaft (52) and the FD shaft (56) at the spline fitting part (54) is suppressed.

Description

Technical Field

[0001] This utility model relates to a connection structure between power transmission shafts in vehicles, which are engaged by splines on the outer diameter side and splines on the inner diameter side. Background Technology

[0002] A connection structure for vehicle power transmission shafts is known, in which the outer diameter side splines and the inner diameter side splines engage. However, a gap exists between the outer diameter side splines and the inner diameter side splines. Due to this gap, the connected shaft deflects at the engagement point, potentially leading to poor tooth contact between the outer diameter side splines and the inner diameter side splines. As a countermeasure, a technique has been disclosed that incorporates a tolerance ring between the outer diameter side splines and the inner diameter side splines to absorb the gap. For example, the spline shaft engagement structure described in Patent Document 1 employs such a technique.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-53384 Utility Model Content

[0006] The problem to be solved by utility models

[0007] Furthermore, using tolerance loops can lead to an increase in the number of components, and is sometimes difficult to implement due to constraints such as installation space, power transmission, and cost. On the other hand, improving the precision of spline teeth to reduce clearance also presents manufacturing and cost challenges. In addition, while changing spline mating to press-fitting reduces deflection, it also worsens assembly disassembly and leads to problems with storage.

[0008] This utility model was developed in light of the above circumstances, and its purpose is to provide a connection structure between power transmission shafts in a vehicle that can suppress shaft deflection at the mating part without requiring additional components or improved component precision, and also ensures assembly decomposition.

[0009] Solution for solving the problem

[0010] The essence of this utility model is a connection structure between power transmission shafts in a vehicle, (a) being engaged by outer diameter side splines and inner diameter side splines, wherein (b) a platform-shaped protrusion is provided at the rear end of the top surface of the outer diameter side spline in the insertion direction and at the rear end of the top surface of the inner diameter side spline in the insertion direction, or at the front end of the top surface of the outer diameter side spline in the insertion direction and at the front end of the top surface of the inner diameter side spline in the insertion direction, to reduce the gap during engagement.

[0011] Effects of the utility model

[0012] According to the present invention, a platform-shaped protrusion is provided at the rear end of the top surface of the outer diameter side spline tooth in the insertion direction and at the rear end of the top surface of the inner diameter side spline tooth in the insertion direction, or at the front end of the top surface of the outer diameter side spline tooth in the insertion direction and at the front end of the top surface of the inner diameter side spline tooth in the insertion direction, to reduce the gap during engagement. This reduces the gap at both ends of the engagement portion and suppresses shaft deflection at the engagement portion. Furthermore, the protrusion can be formed during the finishing stage of the manufacturing process using the top surfaces of the outer diameter side spline tooth and the inner diameter side spline tooth, thus facilitating production, allowing for a smaller gap, and ensuring meshing strength with a space-saving shape. Therefore, it suppresses shaft deflection at the engagement portion without requiring additional components or increased component precision, and also ensures ease of assembly and disassembly. Attached Figure Description

[0013] Figure 1 This is a diagram illustrating the schematic structure of a vehicle to which this utility model is applied.

[0014] Figure 2 This is a diagram illustrating the connection structure between power transmission shafts in a vehicle using this utility model.

[0015] Figure 3 This is an illustration of another embodiment of the present utility model. Figure 2 A fairly accurate diagram.

[0016] Figure 4 This is an illustration of another embodiment of the present utility model. Figure 2 The sectional view is equivalent to the diagram. Detailed Implementation

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018]

Example 1

[0019] Figure 1 This is a diagram illustrating the schematic structure of the vehicle 10 to which this utility model is applied. Figure 1 The vertical direction on the paper indicates the direction of travel for vehicle 10. Figure 1 In this vehicle 10, an engine 12 that functions as a power source, a pair of drive wheels 14, and a power transmission unit 16 are provided. The engine 12 and the power transmission unit 16 are connected via an input shaft 18, and the power transmission unit 16 and the drive wheels 14 are connected via a pair of drive shafts 20. Alternatively, the power source may be an electric motor in addition to the engine 12, or an electric motor may be used instead of the engine 12.

[0020] The engine 12 is, for example, a known internal combustion engine. The electronic control device 80, described later, controls the fuel injection device, ignition device, etc. installed in the vehicle 10, thereby controlling the torque of the engine 12, i.e., the engine torque Te.

[0021] The power transmission unit 16 includes a clutch K1, a hydraulic control circuit 22, a bevel gear 24, a transmission 26, and a limited-slip differential (hereinafter referred to as the LS differential) 58. Power from the engine 12 is transmitted via the input shaft 18 in the order of clutch K1, bevel gear 24, transmission 26, and LS differential 58, and from the LS differential 58 to the drive wheels 14 via the drive shaft 20. The LS differential 58 is a differential device equipped with a differential limiting mechanism.

[0022] Clutch K1 is a friction engagement device, such as a hydraulic one, located between engine 12 and transmission 26. Clutch K1 switches between control states (engaged state, disengaged state) by hydraulic pressure PRk1 supplied from hydraulic control circuit 22.

[0023] The bevel gear 24 is connected to the clutch K1 and the input shaft, i.e., the countershaft 28, which serves as the transmission 26. The power transmitted from the engine 12 via the clutch K1 is transmitted from the rotating shaft in the forward direction of the vehicle 10 to the rotating shaft in the width direction, i.e., the countershaft 28.

[0024] The transmission 26 is a so-called parallel dual-shaft transmission that forms any one of multiple gears (gear stages) GS with different gear ratios (gear ratio is also synonymous) γ (=input speed Ni / output speed No). The input speed Ni is the speed of the countershaft 28, and the output speed No is the speed of the output shaft, i.e., the intermediate shaft (hereinafter referred to as the C-shaft) 52 of the transmission 26.

[0025] The transmission 26 has multiple constantly meshing gear pairs 30. The gear pairs 30, starting from the bevel gear 24 side (input side) in the direction of the rotation axis CL1, sequentially include a reverse gear pair 30a, a 2-speed gear pair 30b, a 1-speed gear pair 30c, a 4-speed gear pair 30d, a 5-speed gear pair 30e, a 6-speed gear pair 30f, and a 3-speed gear pair 30g. The direction of the rotation axis CL1 is synonymous with the axial direction of the countershaft 28.

[0026] The gear pair 30 includes drive gears 32 (including 32a1, 32a2, 32b, 32c, 32d, 32e, 32f, 32g) and driven gears 34 (including 34a, 34b, 34c, 34d, 34e, 34f, 34g) that are always meshed with the drive gears 32. The reverse gear pair 30a includes two drive gears 32a1 and 32a2 to reverse the driving direction. The drive gears 32 are configured not to rotate relative to the countershaft 28. The driven gears 34 are fixed in the direction of the rotation axis CL2 and are able to rotate relative to the C-axis 52. The direction of the rotation axis CL2 is synonymous with the axial direction of the C-axis 52.

[0027] The transmission 26 includes switching mechanisms 36 (including 36a, 36b, 36c, and 36d) configured on the C-axis 52. The first switching mechanism 36a is positioned adjacent to the reverse driven gear 34a in the direction of the rotation axis CL2. The second switching mechanism 36b is positioned adjacent to the 2nd speed driven gear 34b and the 1st speed driven gear 34c. The third switching mechanism 36c is positioned adjacent to the 4th speed driven gear 34d and the 5th speed driven gear 34e. The fourth switching mechanism 36d is positioned adjacent to the 6th speed driven gear 34f and the 3rd speed driven gear 34g.

[0028] The switching mechanism 36 switches the power transmission state of the gear pair 30 to a power transmission capable state and a power transmission incapable state. The switching mechanism 36 is a disconnection device that can switch between a connected state in which one of the drive gears 32 located in adjacent positions is connected to the C-shaft 52 and rotates together, and a disconnected state in which the other is disconnected from the C-shaft 52 and rotates relative to it.

[0029] For example, when the reverse driven gear 34a and the C-shaft 52 are connected via the first switching mechanism 36a, the transmission 26 is switched to a power transmission state via the reverse gear pair 30a, forming the reverse gear position Rev in the transmission 26. The same applies to the 2nd, 1st, 4th, 5th, 6th, and 3rd gear positions.

[0030] In the switching mechanism 36, switching meshing teeth 38 (including 38a, 38b, 38c, 38d, 38e, 38f, and 38g) are formed at positions facing the driven gear 34 in the direction of the rotation axis CL2. In the driven gear 34, gear-side meshing teeth 40 (including 40a, 40b, 40c, 40d, 40e, 40f, and 40g) are formed at positions facing the switching mechanism 36 in the direction of the rotation axis CL2, capable of meshing with the switching meshing teeth 38.

[0031] The transmission 26 is a dog clutch transmission with dog clutches 50 (including 50a, 50b, 50c, 50d, 50e, 50f, and 50g). The dog clutch 50 is a meshing clutch composed of a switching mechanism 36 with switching engagement teeth 38 and gear-side engagement teeth 40. The switching engagement teeth 38 and the gear-side engagement teeth 40 are meshing teeth, i.e., dog clutch teeth, that constitute part of the dog clutch 50. The dog clutch 50 is engaged when the dog clutch teeth mesh with each other, and disengaged when the meshing is released.

[0032] The transmission 26 includes a shift mechanism 60 for moving the shift mechanism 36 in the direction of the rotation axis CL2. The shift mechanism 60 includes shift forks 62 (including 62a, 62b, 62c, 62d) that engage with the shift mechanism 36, a shift cylinder 70, and a shift actuator 66. The shift cylinder 70 is formed with shift grooves 76 (including 76a, 76b, 76c, 76d) that define the movement position of the shift mechanism 36 in the direction of the rotation axis CL2 via the shift forks 62.

[0033] The shift groove 76 is formed circumferentially along the shift cylinder 70, with a portion of its circumferential direction curved axially in the shift cylinder 70. Therefore, when the shift cylinder 70 rotates, the shift fork 62 moves axially along the groove shape of the shift groove 76 in the shift cylinder 70. Furthermore, when the shift fork 62 moves axially in the shift cylinder 70, the shifting mechanism 36 moves in conjunction with the shift fork 62 in the direction of the rotation axis CL2. The shift grooves 76 have different shapes relative to the circumferential position of the shift cylinder 70. The shape of the shift grooves 76 is configured such that as the shift cylinder 70 rotates, the transmission 26 sequentially shifts between reverse (Rev) and 6th gear.

[0034] The transmission 26 shifts gears by moving the switching mechanism 36 to a predetermined position in the direction of the rotation axis CL2 according to the rotation of the shift cylinder 70, thereby switching the disengagement state of the dog clutch 50. The disengagement state of the dog clutch 50 includes a connected state (similar to the engaged state) that allows power transmission between the drive gear 32 and the C-shaft 52, and a disconnected state (similar to the non-engaged state) that disconnects power transmission between the drive gear 32 and the C-shaft 52.

[0035] Power transmission between the C-shaft 52 and the LS differential 58 is carried out via the end drive shaft (hereinafter referred to as the FD shaft) 56. The C-shaft 52, which functions as a vehicle power transmission shaft, is connected to the FD shaft 56 via a spline engagement (spline engagement portion 54). Furthermore, the FD shaft 56 and the LS differential 58 are connected via a drive gear 56a meshing with an end gear 58a. The spline engagement portion 54 corresponds to the "connection structure between vehicle power transmission shafts" of this utility model.

[0036] The vehicle 10 also includes an electronic control unit 80, which serves as a controller for vehicle 10 control devices related to the control of the engine 12, power transmission unit 16, etc. The electronic control unit 80 is configured to include a so-called microcomputer.

[0037] Various signals based on the detection values ​​from various sensors installed in the vehicle 10 are supplied to the electronic control unit 80. These sensors include, for example, an engine speed sensor 90, an input speed sensor 92, an output speed sensor 94, and a throttle opening sensor 96. The various signals include, for example, engine speed Ne, input speed Ni, output speed No, and throttle opening θacc. The output speed No is the speed corresponding to the vehicle speed V.

[0038] The electronic control unit 80 outputs various command signals to various devices installed in the vehicle 10. These devices include, for example, the engine 12, the hydraulic control circuit 22, and the shift actuator 66. The various command signals include, for example, the engine control command signal Se, the hydraulic control command signal Sk1, and the shift cylinder control command signal Sbrl. The shift cylinder control command signal Sbrl is a control command signal used to drive the shift cylinder 70 to rotate.

[0039] The electronic control unit 80 calculates the required drive torque Trdem by applying the throttle opening θacc and vehicle speed V to a pre-set drive requirement mapping, taking into account the gear ratio γ of the transmission 26, and outputs an engine control command signal Se to obtain the engine torque Te that achieves the required drive torque Trdem. Furthermore, the electronic control unit 80 uses a pre-set shift mapping to determine the shift of the transmission 26, and outputs a shift control command signal Sbrl as needed to drive the shift cylinder 70 to rotate and perform shift control of the transmission 26.

[0040] Furthermore, in the spline engagement (spline engagement portion 54) of the C-axis 52 and the FD-axis 56, a clearance fit is used to consider assembly disassembly. In the conventional example, the clearance between the outer diameter side spline tooth 54a and the inner diameter side spline tooth 54b is large. Therefore, the C-axis 52 and the FD-axis 56 may deflect at the spline engagement portion 54, potentially resulting in poor tooth contact between the outer diameter side spline tooth 54a and the inner diameter side spline tooth 54b.

[0041] Therefore, in this embodiment, by Figure 2 The structure shown suppresses deflection at the spline mating part 54. Figure 2 (a) is a perspective view illustrating the structure of the spline fitting part 54. Additionally, Figure 2 (b) is a vertical cross-sectional view of the outer diameter side spline tooth 54a centered on the rotation axis CL2. Figure 2(c) is a vertical cross-sectional view of the inner diameter side spline 54b centered on the rotation axis CL2.

[0042] like Figure 2 As shown in (a) and (b), a platform-shaped protrusion 54a2 (indicated by a slash) is provided at the rear end of the top surface 54a1 of the outer diameter-side spline tooth 54a in the insertion direction to reduce the gap during engagement. The protrusion 54a2 is formed into a specified convex shape, for example, during the finishing stage of the manufacturing process of the top surface 54a1. Furthermore, as... Figure 2 As shown in (a) and (c), a platform-shaped protrusion 54b2 (indicated by a slash) is provided at the rear end of the top surface 54b1 of the inner diameter side spline tooth 54b in the insertion direction to reduce the gap during engagement. The protrusion 54b2 is formed into a specified convex shape, for example, during the finishing stage of the manufacturing process of the top surface 54b1. By providing the protrusions 54a2 and 54b2, the gap at both ends of the spline engagement portion 54 is reduced, and the deflection of the C-axis 52 and FD-axis 56 at the spline engagement portion 54 is suppressed.

[0043] The dimensions of the protrusion 54a2 (e.g., width Xa, length Ya, height Za, tapered treatment not shown, rounded corner treatment, etc.) and the dimensions and positions of the protrusion 54b2 (e.g., width Xb, length Yb, height Zb, distance from the end face Wb, tapered treatment not shown, rounded corner treatment, etc.) are predetermined by design or experimentation to obtain preferred values.

[0044]

Example 2

[0045] Figure 3 It is Figure 2 The example in which the protrusion 54a2 at the rear end of the insertion direction of the top surface 54a1 and the protrusion 54b2 at the rear end of the insertion direction of the top surface 54b1 are changed to a protrusion 54a3 (indicated by a slash) at the front end of the insertion direction of the top surface 54a1 and a protrusion 54b3 (indicated by a slash) at the front end of the insertion direction of the top surface 54b1. In this embodiment, the deflection of the C-axis 52 and the FD-axis 56 at the spline fitting portion 54 is also suppressed by reducing the gap at both ends of the spline fitting portion 54. In addition, the dimensions and positions of the protrusion 54a3 (e.g., width Sa, length Ta, height Ua, distance from the end face Ra, tapered treatment (not shown), rounded corner treatment, etc.) and the dimensions and positions of the protrusion 54b3 (e.g., width Sb, length Tb, height Ub, distance from the end face Rb, tapered treatment (not shown), rounded corner treatment, etc.) are predetermined by design or experimentation, similar to Embodiment 1.

[0046]

Example 3

[0047] Figure 4 It is relative to Figure 2(Example 1) The spline fitting part 54 has a cylindrical surface Pa with a diameter Qa and a length Va at the front end of the spline tooth 54a on the outer diameter side (see reference). Figure 4 (a) A cylindrical surface Pb with diameter Qb and length Vb is provided at the front end of the inner diameter side spline tooth 54b (refer to...). Figure 4 Example (b)). The diameter Qa, length Va, diameter Qb, and length Vb are also pre-set to preferred values ​​through design or experimentation, similar to the other dimensions and positions shown in Example 1. In this embodiment, the deflection of the C-axis 52 and FD-axis 56 at the spline engagement 54 is also suppressed by reducing the gap between the two ends of the spline engagement 54.

[0048] As described above, according to Embodiments 1, 2, and 3, the spline engagement portion 54 has platform-shaped protrusions 54a2 and 54b2 at the rear end of the insertion direction of the top surface 54a1 of the outer diameter side spline tooth 54a and the rear end of the insertion direction of the top surface 54b1 of the inner diameter side spline tooth 54b, respectively, to reduce the gap during engagement. Alternatively, platform-shaped protrusions 54a3 and 54b3 are provided at the front end of the insertion direction of the top surface 54a1 of the outer diameter side spline tooth 54a and the front end of the insertion direction of the top surface 54b1 of the inner diameter side spline tooth 54b, respectively, to reduce the gap during engagement. This reduces the gap at both ends of the spline engagement portion 54, suppressing the deflection of the C-axis 52 and the FD-axis 56 at the spline engagement portion 54. Furthermore, the protrusions (54a2, 54b2 or 54a3, 54b3) can be formed during the finishing stage of the manufacturing process, utilizing the top surfaces 54a1 and 54b1. This facilitates production, allows for smaller clearances, and ensures meshing strength with a space-saving shape. Consequently, it eliminates the need for additional components or increased component precision, suppresses deflection of the C-axis 52 and FD-axis 56 at the spline engagement portion 54, and also ensures ease of assembly and disassembly.

[0049] The embodiments of the present invention have been described in detail above based on the accompanying drawings, but the present invention can also be applied to other methods.

[0050] For example, in the above embodiments, the present invention is applied to the spline engagement portion 54 between the power transmission shafts, namely the C-shaft 52 and the FD-shaft 56, of the power transmission unit 16 of the vehicle 10, but it is not limited to this method. For example, the present invention can be applied to any part where spline engagement is performed with a clearance fit.

[0051] Furthermore, the above description is only one embodiment, and the present invention can be implemented in various ways with modifications and improvements based on the knowledge of those skilled in the art.

[0052] Explanation of reference numerals in the attached figures

[0053] 54: Spline mating part (connection structure between power transmission shafts in vehicles) 54a: outer diameter side spline teeth 54a1: top surface 54a2, 54a3, 54b2, 54b3: protrusions 54b: inner diameter side spline teeth 54b1: top surface.

Claims

1. A connection structure between power transmission shafts in a vehicle, characterized in that, they engage via splines on the outer diameter side and splines on the inner diameter side, and are further characterized in that, The rear end of the top surface of the spline tooth on the outer diameter side in the insertion direction and the rear end of the top surface of the spline tooth on the inner diameter side in the insertion direction, Alternatively, at the insertion front end of the top surface of the outer diameter side spline tooth and at the insertion front end of the top surface of the inner diameter side spline tooth. It is provided with a platform-shaped protrusion that reduces the gap during engagement.

Images