Boot replacement determination device for vehicle drive shaft

Abstract

To provide a boot replacement determination device for a vehicle drive shaft that can determine an appropriate timing for replacing a boot before the boot is damaged.SOLUTION: A boot replacement determination unit 62 determines replacement of a boot 40e on the basis of a cumulative value ΣΣL40 and / or ΣΣA40 of a slide amount L40 and / or a rotation angle A40 of a differential-side constant velocity joint 40. As a result, the replacement of the boot 40e is determined at an appropriate timing sufficiently before the boot 40e is damaged. Similarly, the boot replacement determination unit 62 determines replacement of a boot 42g on the basis of the cumulative value ΣΣA42 of the rotation angle A42 of the wheel-side constant velocity joint 42. As a result, the replacement of the boot 42g is determined at an appropriate timing sufficiently before the boot 42g is damaged.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a boot replacement determination device for a vehicle drive shaft that determines replacement of a boot of a joint for a vehicle drive shaft.

Background Art

[0002] In the power transmission path of a vehicle, a drive shaft that connects between a differential gear device and a drive wheel that supports the vehicle body via a suspension device is provided with a flexible joint having a boot such as a ball-and-socket type constant velocity joint or a tripod type constant velocity joint in order to allow vertical movement of the drive wheel.

[0003] The boot is formed in a bag shape having a plurality of folds so as to cover the joint in order to prevent foreign matter from entering the joint or to prevent the lubricating grease inside the joint from leaking, and is provided on the drive shaft. Since this boot is made of an elastic material such as synthetic rubber in order to be elastically deformable, it is necessary to manage the durability life as a component.

[0004] Patent Document 1 discloses a determination system that determines breakage of a boot by analyzing an image of the boot, or acquires a visual inspection result of the boot, determines breakage of the boot based on the inspection result, and determines component replacement if there is breakage.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the above prior art, the durability of the boot is not determined based on the mechanical fatigue of the boot, but the breakage of the boot is determined from the appearance of the boot. Therefore, there is a possibility that the replacement of the boot may be delayed. In particular, in the drive shaft used for the De Dion type suspension device, the deformation of the boot is large, and such inconvenience has been remarkable.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a boot replacement determination device for a vehicle drive shaft that can determine the replacement of a boot at an appropriate time before the boot breaks.

Means for Solving the Problems

[0008] In order to achieve such an object, the gist of the present invention is as follows: (1) A boot replacement determination device for a vehicle drive shaft that determines the replacement of a boot provided in a universal joint of a drive shaft that connects between a differential gear device of a vehicle and a drive wheel that supports a vehicle body via a suspension device, and (2) A boot replacement determination unit that determines the replacement of the boot based on the cumulative value of the slide amount and / or the rotation angle of the universal joint.

Effects of the Invention

[0009] According to the boot replacement determination device for a vehicle drive shaft of the present invention, the boot replacement determination unit determines the replacement of the boot based on the cumulative value of the slide amount and / or the rotation angle of the universal joint. Thereby, the replacement of the boot is determined at an appropriate time before the boot breaks.

[0010] Here, preferably, the slide amount and the rotation angle of the universal joint are respectively calculated based on the stroke amount of the suspension device detected by a stroke sensor from a previously stored relationship. The stroke amount of the suspension device is the movement amount of the component of the suspension device corresponding to the vertical relative movement amount of the drive wheel that supports the vehicle body via the suspension device with respect to the vehicle body.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that in the drawings used in the following description, the dimensional ratios of respective parts are not necessarily drawn accurately. EXAMPLE

[0013] FIG. 1 shows a vehicle 18 in which a pair of left drive wheels 10 and right drive wheels 12 support a vehicle body 16 via a De Dion type suspension device 14. The De Dion type suspension device 14 basically includes a rear axle 24 connected between a pair of left bearing boxes 20 and right bearing boxes 22 that rotatably support a pair of left drive wheels 10 and right drive wheels 12, which are rear wheels for example, and a pair of left springs 26 and right springs 28 that support the vehicle body 16 and are located at both ends of the rear axle 24, and also includes links (not shown).

[0014] A differential gear device 30 is fixed to the center in the width direction of the lower surface of the vehicle body 16, and a pair of left drive shafts 32 and right drive shafts 34 are connected between the differential gear device 30 and the left drive wheels 10 and the right drive wheels 12. Since the left drive shaft 32 and the right drive shaft 34 are similarly configured, hereinafter, the configuration and determination control of boot replacement will be described by taking the left drive shaft 32 as a representative.

[0015] As shown in FIG. 2, the left drive shaft 32 includes a shaft body 35, a differential side connecting shaft 36 connected to the side gear of the differential gear device 30, a wheel side connecting shaft 38 connected to the left drive wheel 10, a differential side constant velocity joint 40 connecting between the shaft body 35 and the differential side connecting shaft 36, and a wheel side constant velocity joint 42 connecting between the shaft body 35 and the wheel side connecting shaft 38. The angle between the differential side connecting shaft 36 and the wheel side connecting shaft 38 is freely adjustable, and the axial distance between the differential side connecting shaft 36 and the wheel side connecting shaft 38 is freely adjustable, so as to transmit the power output from the differential gear device 30 to the left drive wheel 10.

[0016] The differential side constant velocity joint 40 is, for example, a tripod type sliding constant velocity joint having a telescopic function. The wheel side constant velocity joint 42 is, for example, a Bifolde type fixed constant velocity joint without a telescopic function.

[0017] The differential side constant velocity joint 40 is fixed to the end of the shaft body 35 on the differential gear device 30 side, and includes a tripod 40b provided with three trunnions 40a protruding to the outer peripheral side at equal angular intervals, three guide grooves 40c for guiding the three trunnions 40a, a bottomed cylindrical outer ring 40d that houses the tripod 40b so as not to be relatively rotatable and movable in the direction of the rotation center line, and a bellows-shaped boot 40e fixed to the end of the shaft body 35 on the differential gear device 30 side and the outer ring 40d so as to cover the opening of the outer ring 40d and holding high-viscosity grease inside. The change amount of the slide amount of the tripod 40b in the direction of the rotation center line of the outer ring 40d (the relative movement amount in the direction of the rotation center line between the outer ring 40d and the end of the shaft body 35) corresponds to the deformation amount in the slide direction of the boot 40e. The rotation angle of the differential side constant velocity joint 40 (the change amount of the intersection angle between the rotation center line of the outer ring 40d and the rotation center line of the shaft body 35) corresponds to the rotation deformation angle amount of the boot 40e.

[0018] The wheel-side constant velocity joint 42 is fixed to the end of the shaft body 35 on the left driving wheel 10 side, and a plurality of arc-shaped grooves 42a are formed at equal angular intervals around the rotation center line in a cross section passing through the rotation center line of the shaft body 35. It includes a partial spherical inner ring 42b, a cup-shaped outer ring 42d in which a plurality of grooves 42c facing the plurality of arc-shaped grooves 42a are formed on the inner peripheral surface of the hemispherical hole, a retainer 42f that holds the rolling elements 42e fitted into the arc-shaped grooves 42a and the arc-shaped grooves 42c, and a bellows-shaped boot 42g that is fixed to the end of the shaft body 35 on the driving wheel 10 side and the outer ring 42d so as to cover the opening of the outer ring 42d and holds highly viscous grease inside. The rotation angle of the wheel-side constant velocity joint 42 (the change amount of the intersection angle between the rotation center line of the shaft body 35 and the rotation center line of the outer ring 42d) corresponds to the rotation deformation angle amount of the boot 42g.

[0019] Returning to FIG. 1, on the vehicle body 16, there are provided a left stroke sensor 48 that detects the movement amount of the left end of the suspension device 14, that is, the suspension stroke ΔLH, a right stroke sensor 50 that detects the movement amount of the right end of the suspension device 14, that is, the suspension stroke ΔRH, and a communication device 54 that sequentially transmits the suspension stroke ΔLH detected by the left stroke sensor 48 and the suspension stroke ΔRH detected by the right stroke sensor 50 to the server 52. The suspension strokes ΔLH and ΔRH are, for example, the vertical relative movement amounts of the left end and the right end of the rear axle 24 with respect to the vehicle body 16 with respect to the vehicle body 16. The slide amount and rotation angle of the differential-side constant velocity joint 40, the rotation angle of the wheel-side constant velocity joint 42, the slide amount and rotation angle of the differential-side constant velocity joint 40, the deformation amount in the slide direction and the rotation angle deformation amount of the boot 40e provided on the differential-side constant velocity joint 40, and the rotation angle deformation amount of the boot 40g provided on the wheel-side constant velocity joint 42 are mechanically in a one-to-one relationship with the suspension stroke ΔLH of the suspension device 14.

[0020] In FIG. 3, the electronic control device 56 is constituted by a computer and functions as, for example, a boot replacement determination device provided in a parts management company. The electronic control device 56 functionally includes a data acquisition unit 58, a boot load estimation unit 60, a boot replacement determination unit 62, a storage unit 64, and an output unit 66.

[0021] The data acquisition unit 58 acquires data on the suspension stroke ΔLH and the suspension stroke ΔRH transmitted from the vehicle 18 and stored in the server 52 at a preset fixed period, for example, every day, every month, or every year, and stores the data in the storage unit 64.

[0022] For the left drive shaft 32, the boot load estimation unit 60, based on the suspension stroke ΔLH for each suspension stroke ΔLH included in the acquired data, that is, for each up-and-down vibration of the vehicle body 16, from the pre-stored relationship between the suspension stroke ΔLH and the slide amount L40, the rotation angle A40, and the rotation angle A42 of the differential side constant velocity joint 40, sequentially calculates the slide amount L40, the rotation angle A40 of the differential side constant velocity joint 40, and the slide amount L42 of the wheel side registerable joint 42.

[0023] The boot load estimation unit 60 calculates, for each of the fixed periods, the integrated values ΣL40 and ΣA40 of the slide amount L40 and the rotation angle A40 of the differential side constant velocity joint 40 within the fixed period, and the integrated value ΣA42 of the rotation angle A42 of the wheel side constant velocity joint 42 within the fixed period.

[0024] Then, the boot load estimation unit 60 calculates the cumulative value ΣΣL40 of the slide amount of the differential side constant velocity joint 40 by adding the cumulative value ΣL40 of the current new constant cycle to the sum of the integrated values up to the previous cycle with respect to the slide amount L40 of the differential side constant velocity joint 40. Further, the boot load estimation unit 60 calculates the cumulative value ΣΣA40 of the rotation angle of the differential side constant velocity joint 40 by adding the new ΣA40 to the sum of the integrated values up to the previous cycle with respect to the rotation angle of the differential side constant velocity joint 40. Furthermore, the boot load estimation unit 60 calculates the cumulative value ΣΣA42 of the rotation angle of the wheel side constant velocity joint 42 by adding the integrated value ΣA42 of the new cycle to the sum of the integrated values up to the previous cycle with respect to the rotation angle of the wheel side constant velocity joint 42. The boot load estimation unit 60 stores the above calculation results in the storage unit 64.

[0025] The cumulative value ΣΣL40 and the cumulative value ΣΣA40 correspond to the cumulative load of the deformation in the slide direction and the angular deformation input to the boot 40e of the left drive shaft 32, and the cumulative value ΣΣA42 corresponds to the cumulative load of the angular deformation input to the boot 42g of the left drive shaft 32.

[0026] The boot replacement determination unit 62 determines to replace the boot 40e when the cumulative value ΣΣL40 of the slide amount L40 of the differential side constant velocity joint 40 is equal to or greater than the boot replacement determination value Lej for the preset slide direction deformation amount with respect to the boot 40e of the left drive shaft 32, and determines to replace the boot 40e when the cumulative value ΣΣA40 of the rotation angle A40 of the differential side constant velocity joint 40 is equal to or greater than the boot replacement determination value Aej for the preset deformation angle amount. Further, the boot replacement determination unit 62 determines to replace the boot 42g when the cumulative value ΣΣA42 of the response angle A42 of the differential side constant velocity joint 40 is equal to or greater than the boot replacement determination value Agj for the preset rotation deformation angle amount with respect to the boot 42g of the left drive shaft 32. The boot replacement determination unit 62 stores the above determination results in the storage unit 64.

[0027] For the boot 40e, the boot replacement determination value Lej for the amount of deformation in the sliding direction and the boot replacement determination value Aej for the amount of deformation angle are set to values well before reaching the breakage of the boot 40e, based on the results of repeated tests of the sliding amount and rotational deformation performed in advance. Similarly, for the boot 42g, the boot replacement determination value Agj for the amount of rotational deformation angle is set to a value well before reaching the breakage of the boot 42g, based on the results of repeated tests of angular deformation performed in advance.

[0028] The output unit 66 causes the display 68 to display the determination result by the boot replacement determination unit 62 and transmits it to other devices as necessary.

[0029] Figure 4 is a flowchart for explaining the main part of the control operation of the electronic control device. In Figure 4, in step S1 corresponding to the data acquisition unit 58 (hereinafter, steps are omitted), data on the suspension stroke ΔLH and the suspension stroke ΔRH stored in the server 52 are acquired at each of the predetermined periods. Next, S2 and S3 corresponding to the boot load estimation unit 60 are executed.

[0030] In S2, for the left drive shaft 32, based on the relationship stored in advance between the suspension stroke ΔLH and the slide amount L40, rotation angle A40 of the differential side constant velocity joint 40 of the differential side constant velocity joint 40, and the rotation angle A42 of the wheel side constant velocity joint 42, for each suspension stroke ΔLH included in the acquired data, that is, for each up and down vibration of the vehicle body 16, the slide amount L40, rotation angle A40 of the differential side constant velocity joint 40 of the differential side constant velocity joint 40, and the rotation angle A42 of the wheel side constant velocity joint 42 are sequentially calculated.

[0031] In S3, for the differential side constant velocity joint 40 of the left drive shaft 32, the integrated value ΣL40 of the slide amount L40 within the fixed period, the integrated value ΣA40 of the rotation angle A40 within the fixed period, and the integrated value ΣA42 of the rotation angle A42 of the wheel side constant velocity joint 42 within the fixed period are calculated for each fixed period. Then, regarding the deformation amount in the slide direction of the boot 40e, the cumulative value ΣΣL40 of the movement amount in the slide direction of the differential side constant velocity joint 40 is calculated by adding the integrated value ΣL40 of the new fixed period to the total value of the integrated value ΣL40 up to the previous period. Also, regarding the rotation angle of the differential side constant velocity joint 40, the cumulative value ΣΣA40 of the rotation angle of the differential side constant velocity joint 40 is calculated by adding the new ΣA40 to the total value of the integrated value ΣA40 up to the previous period. Further, regarding the rotation angle of the wheel side constant velocity joint 42, the cumulative value ΣΣA42 of the rotation angle of the wheel side constant velocity joint 42 is calculated by adding the new ΣA42 to the total value of the integrated value ΣA42 up to the previous period.

[0032] In S4 corresponding to the boot replacement determination unit 62, for the differential side constant velocity joint 40 of the left drive shaft 32, it is determined whether the cumulative value ΣΣ40 of the slide amount L40 is equal to or greater than the boot replacement determination value Lej, whether the cumulative value ΣΣA40 of the deformation angle A40 is equal to or greater than the boot replacement determination value Aej, and for the wheel side constant velocity joint 42 of the left drive shaft 32, whether the cumulative value ΣΣA42 of the rotation angle A42 is equal to or greater than the boot replacement determination value Agj.

[0033] If any of the determinations in S4 is negative, this routine ends. However, if any of those determinations is affirmative, in S5 corresponding to the output unit 66, an output for boot replacement is performed for the boot for which the determination was affirmative. For example, if it is determined that the cumulative value ΣΣL40 of the slide amount L40 has become equal to or greater than a preset boot replacement determination value Lej, or if it is determined that the cumulative value ΣΣA40 of the deformation angle A40 has become equal to or greater than the boot replacement determination value Aej, an output indicating replacement of the boot 40e of the left drive shaft 32 is performed. Also, if it is determined that the cumulative value ΣΣA42 of the rotation angle A42 has become equal to or greater than the boot replacement determination value Agj, an output indicating replacement of the boot 42g of the left drive shaft 32 is performed.

[0034] As described above, according to the electronic control device 56 of the present embodiment, the boot replacement determination unit 62 determines replacement of the boot 40e based on the cumulative value ΣΣL40 and / or ΣΣA40 of the slide amount L40 and / or the rotation angle A40 of the differential side constant velocity joint 40. Thereby, replacement of the boot 40e is determined at an appropriate time well before the boot 40e tears. Similarly, the boot replacement determination unit 62 determines replacement of the boot 42g based on the cumulative value ΣΣA42 of the rotation angle A42 of the wheel side constant velocity joint 42. Thereby, replacement of the boot 42g is determined at an appropriate time well before the boot 42g tears. Such an effect is remarkable in a De Dion type suspension device 14, for example, in which the slide amount is about four times larger than that of an independent suspension device.

[0035] In the foregoing embodiment, the description was based on the drawings, but the present invention is applied in other aspects.

[0036] For example, the electronic control device 56 that functions as the boot replacement determination device of the foregoing embodiment was applied to the boots 40e and 42g provided on the left drive shaft 32 and the right drive shaft 34 between the differential gear device 30 and the left drive wheel 10 and the right drive wheel 12 that are the rear wheels, but it may also be applied to the boots of the drive shafts provided in the front wheel suspension device.

[0037] In addition, the vehicle 18 in the above-described embodiment may be any of an engine vehicle equipped with an engine as a power source, a BEV vehicle equipped with an electric motor as a power source, an HEV vehicle, a PHEV vehicle, an FCEV vehicle, and the like.

[0038] In the above-described embodiment, the boot replacement determination unit 62 determines the replacement of the boot 40e of the left drive shaft 32 based on the cumulative value ΣΣLlem of the deformation amount Llem in the sliding direction and the cumulative value ΣΣAlem of the deformation angle Alem. However, the replacement of the boot 40e may be determined based on either the cumulative value ΣΣLlem of the deformation amount Llem in the sliding direction or the cumulative value ΣΣAlem of the deformation angle Alem.

[0039] In addition, the above-described electronic control device 56 may be mounted on the vehicle 10.

[0040] Note that the above is merely an application example of the present invention, and the present invention may be implemented with various modifications without departing from the spirit thereof.

Explanation of Reference Numerals

[0041] 30: Differential gear device, 32: Left drive shaft, 34: Right drive shaft, 40e: Boot, 42: Wheel-side constant velocity joint, 42g: Boot, 56: Electronic control device, 58: Data acquisition unit, 60: Boot load estimation unit, 62: Boot replacement determination unit, 64: Storage unit, 66: Output unit, 68: Display

Claims

【Claim 1】 A boot replacement determination device for a vehicle drive shaft that determines replacement of a boot provided in a universal joint of a drive shaft that connects between a differential gear device of a vehicle and a drive wheel that supports a vehicle body via a suspension device, comprising a boot replacement determination unit that determines replacement of the boot based on a cumulative value of a slide amount and / or an angle of the universal joint. A boot replacement determination device for a vehicle drive shaft, characterized by the above.

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