WO2024018529A1

WO2024018529A1 - Universal joint

Info

Publication number: WO2024018529A1
Application number: PCT/JP2022/028067
Authority: WO
Inventors: 諭史吉田
Original assignee: 株式会社ジェイテクト
Priority date: 2022-07-19
Filing date: 2022-07-19
Publication date: 2024-01-25

Abstract

A universal joint 10 comprises: a cross shaft 11 which has a trunnion 11a; a bearing cup 12 which supports the trunnion 11a via plurality of rollers 15; a yoke 13 to which the bearing cup 12 is attached; a fastening member 14 which fixes the bearing cup 12 to the yoke 13; and a pressure sensor 40. The bearing cup 12 has: a first surface 20 which includes a first contact surface 22 that contacts the yoke 13 and a key 24 which protrudes with respect to the first contact surface 22; and a through hole 25 which is open in the first contact surface 22 and through which the fastening member 14 passes. The yoke 13 has: a second surface 26 which includes a second contact surface 30 that contacts the first contact surface 22 and a key groove 23 that is recessed with respect to the second contact surface 30 and that fits with the key 24; a fastening hole 28 which is open in the second contact surface 30 and in which the fastening member 14 is fastened; and a liquid pressure chamber 42 inside which a liquid L is filled. The pressure sensor 40 measures the pressure of the liquid L. At least part of the liquid pressure chamber 42 is positioned between the key groove 23 and the fastening hole 28.

Description

universal joint

The present invention relates to a universal joint.

Patent Document 1 discloses a large universal joint used for drive shafts of rolling mills, etc.

Japanese Patent Application Publication No. 2006-77873

In order to measure the torque acting on the drive shaft of a rolling mill in which the universal joint is employed, it is conceivable to attach a strain gauge to the drive shaft, for example. The torque acting on the drive shaft is measured based on the output of the strain gauge.
However, to measure torque using a strain gauge, it is necessary to connect, in addition to the strain gauge, a transmitter, a bridge circuit, etc. to obtain the output of the strain gauge when the drive shaft rotates. Furthermore, since a large number of cables are required to connect these devices, the device configuration for torque measurement is often relatively complex. Furthermore, it is possible that the strain gauge may be damaged due to excessive torque that is instantaneously generated.

The universal joint connected to the drive shaft includes a plurality of parts.
The inventor of the present application focused on this point, and determined that the torque of the drive shaft can be measured with a relatively simple configuration by measuring the stress acting on some of the multiple parts included in the universal joint. We have thought about what we can do and have created embodiments according to the present disclosure.

The universal joint of this embodiment includes a cross shaft having a trunnion, a bearing cup that supports the trunnion via a plurality of rollers, a yoke to which the bearing cup is attached, and a fastener that fixes the bearing cup to the yoke. The device includes a member and a pressure sensor. The bearing cup has a first surface that includes a first contact surface that contacts the yoke and a key that projects with respect to the first contact surface, and an opening in the first contact surface through which the fastening member passes. It has a through hole. The yoke includes a second abutting surface that abuts the first abutting surface, a second surface that is recessed with respect to the second abutting surface, and includes a keyway into which the key is fitted, and a second abutting surface that is in contact with the second abutting surface. It has a fastening hole that is open and into which the fastening member is fastened, and a hydraulic chamber filled with liquid. The pressure sensor measures the pressure of the liquid. At least a portion of the hydraulic chamber is located between the keyway and the fastening hole.

According to the present disclosure, it is possible to obtain a universal joint that allows torque measurement with a simple configuration.

FIG. 1 is a diagram showing a universal joint according to an embodiment. FIG. 2 is an exploded perspective view of the universal joint according to the embodiment. FIG. 3 is a partial sectional view taken along the line III--III in FIG. 4 is a partial sectional view taken along the line IV-IV in FIG. 3. FIG. FIG. 5 is a block diagram showing a configuration example of a pressure sensor and a data processing device. FIG. 6 is a diagram showing a universal joint according to a modified example.

First, the contents of the embodiment will be listed and explained.
[Overview of embodiment]
(1) The universal joint of this embodiment includes a cross shaft having a trunnion, a bearing cup that supports the trunnion via a plurality of rollers, a yoke to which the bearing cup is attached, and a yoke that attaches the bearing cup to the yoke. It includes a fastening member for fixing and a pressure sensor. The bearing cup has a first surface that includes a first contact surface that contacts the yoke and a key that projects with respect to the first contact surface, and an opening in the first contact surface through which the fastening member passes. It has a through hole. The yoke includes a second abutting surface that abuts the first abutting surface, a second surface that is recessed with respect to the second abutting surface, and includes a keyway into which the key is fitted, and a second abutting surface that is in contact with the second abutting surface. It has a fastening hole that is open and into which the fastening member is fastened, and a hydraulic chamber filled with liquid. The pressure sensor measures the pressure of the liquid. At least a portion of the hydraulic chamber is located between the keyway and the fastening hole.

When torque acts on the universal joint via a drive shaft or the like, stress corresponding to the torque acts on the yoke through the bearing cup. The yoke is slightly elastically deformed by this stress. At this time, the pressure of the liquid in the hydraulic pressure chamber provided in the yoke changes depending on the magnitude of stress acting on the yoke. In other words, the pressure of the liquid in the hydraulic chamber changes depending on the magnitude of the torque acting on the universal joint.
In particular, compressive stress acts on the keyway of the yoke. This compressive stress is caused by the keyway being pressed by the key, or by the key being pressed by the keyway.
In this embodiment, at least a portion of the hydraulic chamber is located between the keyway and the fastening hole. Therefore, the hydraulic chamber is located near the keyway. The compressive stress acts on the hydraulic chamber. As a result, changes in stress due to torque acting on the universal joint appear as changes in fluid pressure.
Therefore, the universal joint of this embodiment can measure the torque acting on the universal joint based on the output of the pressure sensor.
In this way, the universal joint of this embodiment can measure torque by measuring the pressure of the liquid in the hydraulic chamber. Compared to the above, a bridge circuit or the like is not required, and wiring etc. can be easily routed. As a result, the universal joint of this embodiment can measure torque with a simple configuration. Further, in the universal joint of this embodiment, the hydraulic chamber is not destroyed by excessive torque that is instantaneously generated.

(2) In the universal joint, the hydraulic chamber may be located between the bottom surface of the keyway and the second contact surface in an axial direction parallel to the central axis of the universal joint. preferable.
In this case, the hydraulic pressure chamber can be reliably provided between the keyway and the fastening hole.

(3) In the universal joint of this embodiment, compressive stress acts on the keyway along the circumferential direction. Therefore, in the universal joint of this embodiment, compressive stress acts on the keyway over the entire longitudinal direction of the keyway.
In this regard, in the above universal joint, when the key and the keyway extend along a radial direction perpendicular to the central axis, the hydraulic pressure chamber is a cylindrical hole extending in the longitudinal direction of the keyway. It is preferable to include.
In this case, the universal joint of this embodiment can ensure a wide range in the longitudinal direction of the keyway where the hydraulic pressure chamber and the keyway are lined up in the vicinity. As a result, the universal joint according to the present embodiment is able to more noticeably cause a change in liquid pressure due to a change in stress.

[Details of embodiment]
Hereinafter, preferred embodiments will be described with reference to the drawings.
[About the overall structure]
FIG. 1 is a diagram showing a universal joint according to an embodiment. FIG. 2 is an exploded perspective view of the universal joint according to the embodiment.
This universal joint 10 is used, for example, in a rolling mill in a steel mill. More specifically, the universal joint 10 is disposed between the input shaft of the rolling roll and the drive shaft, or between the output shaft of the drive motor and the drive shaft, and connects the pair of shafts so that they can rotate together. . The universal joint 10 transmits rotational force from one of the pair of shafts to the other.

The universal joint 10 includes one cross shaft 11, four bearing cups 12, a pair of yokes 13, and a plurality of fastening members 14.
The plurality of fastening members 14 are members for fixing the bearing cup 12 to the yoke 13. The plurality of fastening members 14 are, for example, bolts.
The cross shaft 11 has four trunnions 11a.
Each bearing cup 12 supports each trunnion 11a via a plurality of rollers 15. All bearing cups 12 have the same configuration.
Each bearing cup 12 is attached to a pair of yokes 13.

The pair of yokes 13 are integrally rotatably connected to a pair of shafts (not shown) in a rolling mill.
Of the pair of yokes 13, the first yoke 13a shown on the right side in FIGS. 1 and 2 is included in the first shaft 16. The first yoke 13a can rotate integrally with the first shaft 16. The first shaft 16 is connected to one of a pair of shafts in the rolling mill.
Of the pair of yokes 13, the second yoke 13b shown on the left side in FIGS. 1 and 2 is included in the second shaft 17. The second yoke 13b can rotate integrally with the second shaft 17. The second shaft 17 is connected to the other shaft of the pair of shafts in the rolling mill.
The first yoke 13a and the second yoke 13b have the same configuration.

Here, when the central axis of the first shaft 16 (first yoke 13a) and the central axis of the second shaft 17 (second yoke 13b) are arranged in the same straight line (the state shown in FIG. 1), The direction along the central axis C is the "axial direction." In the invention of the present disclosure, the "axial direction" also includes a direction parallel to the central axis C.
Further, the direction perpendicular to the central axis C is the "radial direction". The direction of rotation around the central axis C is the "circumferential direction."

As shown in FIG. 2, each bearing cup 12 has a first surface 20 facing the yoke 13 and a plurality of through holes 25. As shown in FIG.
The first surface 20 includes a first contact surface 22 that contacts the yoke 13 and a key 24 .
The key 24 projects in a rectangular shape with respect to the first contact surface 22.
The plurality of through holes 25 are provided in parallel to the axial direction. The plurality of through holes 25 penetrate between the first surface 20 and the first opposite surface 19. The first opposite surface 19 is a surface of the bearing cup 12 that faces opposite to the first surface 20 .
In this embodiment, a total of six through holes 25 are provided, three on both sides of the bearing cup 12 in the circumferential direction. The plurality of through holes 25 open into two regions 22 a of the first contact surface 22 adjacent to each other on both sides of the key 24 in the circumferential direction. Three through holes 25 open in each of the two regions 22a.

Two sets of the pair of bearing cups 12 are attached to each of the pair of yokes 13. The following description will explain the configuration of the first yoke 13a. On the other hand, the configuration of the second yoke 13b is similar to the configuration of the first yoke 13a.
The first yoke 13a has a second surface 26 that faces the first surface 20 of the bearing cup 12, and a plurality of fastening holes 28.
The second surface 26 includes a pair of second contact surfaces 30 and a pair of keyways 23 . Each of the pair of second abutting surfaces 30 is a surface that abuts the first abutting surface 22 of one of the bearing cups 12 of the pair.
The pair of second contact surfaces 30 are provided on both sides of the second surface 26 in the radial direction with the central axis C interposed therebetween.

The pair of keyways 23 are recessed relative to the pair of second contact surfaces 30. The keys 24 of the pair of bearing cups 12 are fitted into the pair of key grooves 23.
The pair of keyways 23 each extend in the radial direction from the outer peripheral surface 13g of the first yoke 13a. Therefore, the keyway 23 is provided so as to cut out the outer peripheral surface 13g.

The plurality of fastening holes 28 are provided in each of the pair of second contact surfaces 30.
The plurality of fastening holes 28 open in two regions 30 a of the second contact surface 30 adjacent to both sides of the keyway 23 in the circumferential direction. Three fastening holes 28 open in each of the two regions 30a.
A female thread is formed on the inner peripheral surface of the fastening hole 28. A male thread provided at the tip of the fastening member 14 is screwed into this female thread.

The fastening member 14 is inserted into the through hole 25 from the first opposite surface 19 side of the bearing cup 12 and is screwed into the fastening hole 28 .
Thereby, the bearing cup 12 is fixed to the second surface 26 of the first yoke 13a. At this time, the first contact surface 22 of the bearing cup 12 and the second contact surface 30 of the first yoke 13a contact each other.

The universal joint 10 of this embodiment further includes a pressure sensor 40.
The pressure sensor 40 measures the pressure of the liquid filled in the hydraulic pressure chamber 42 provided in the first yoke 13a.

[About the hydraulic chamber]
The above-described hydraulic chamber 42 is provided in the first yoke 13a of this embodiment.
FIG. 3 is a partial sectional view taken along the line III--III in FIG.
As shown in FIG. 3, the hydraulic chamber 42 is configured by a hole 44 and an internal space of an adapter 46. As shown in FIG.

The hole 44 is open to the outer peripheral surface 13g of the first yoke 13a. The hole 44 has a first cylindrical surface 44a and a bottom surface 44b. The first cylindrical surface 44a is a surface connecting the outer peripheral surface 13g and the bottom surface 44b. The first cylindrical surface 44a extends along the longitudinal direction of the keyway 23.
4 is a partial sectional view taken along the line IV-IV in FIG. 3. FIG.
In FIG. 4, the keyway 23 has a bottom surface 23a and a pair of stepped surfaces 23b. The pair of stepped surfaces 23b are surfaces that connect the pair of long sides of the bottom surface 23a and the two regions 30a on both sides of the keyway 23.
As shown in FIGS. 3 and 4, the hole 44 is provided between the keyway 23 and the fastening hole 28. Therefore, the hydraulic chamber 42 is located between the keyway 23 and the fastening hole 28.
Further, as shown in FIG. 4, the hole 44 is provided between the bottom surface 23a of the keyway 23 and the region 30a (second contact surface 30) in the axial direction. Therefore, the hydraulic chamber 42 is located between the bottom surface 23a and the second contact surface 30 in the axial direction.

Furthermore, when torque is transmitted between the key 24 and the keyway 23, the stepped surface 23b on the side of the torque generation source presses the key 24. The key 24 on the side receiving the torque presses the stepped surface 23b. As a result, compressive stress acts on the surface layer portion when the step surface 23b is the surface, and a region that is slightly plastically deformed is generated.
Therefore, in FIG. 4, the distance W between the stepped surface 23b and the hole 44 is set to a value that does not cause plastic deformation in the hole 44.
As a result, plastic deformation occurring in the surface layer of the stepped surface 23b does not affect the hydraulic pressure chamber 42.

As shown in FIG. 3, the adapter 46 is attached to the outer end 44a1 of the first cylindrical surface 44a.
As shown in FIG. 2, the adapter 46 is a T-shaped fitting. The adapter 46 has a first tube 46a extending in the radial direction and a second tube 46b extending in the axial direction.
The first pipe 46a is connected to the second pipe 46b at approximately the center in the longitudinal direction. Moreover, the first pipe 46a and the second pipe 46b are in communication with each other.

As shown in FIG. 3, a distal end portion 46a1 of the first tube 46a facing radially inward is press-fitted into an outer end portion 44a1.
As shown in FIG. 1, the pressure sensor 40 is provided at the tip 46b1 of the second pipe 46b facing toward the second yoke 13b. Pressure sensor 40 is fixed to the outside of bearing cup 12 .
A valve 48 is provided at a distal end portion 46b2 of the second tube 46b facing in the opposite direction to the distal end portion 46b1. The valve 48 can be opened and closed, and can be switched between communicating and blocking communication between the inside and outside of the hydraulic chamber 42.

As shown in FIG. 3, the liquid L is filled inside the hydraulic pressure chamber 42. As shown in FIG. Note that the connecting portion between the hole 44 and the adapter 46, the connecting portion between the adapter 46 and the pressure sensor 40, and the connecting portion between the adapter 46 and the valve 48 are sealed. The liquid L in the hydraulic pressure chamber 42 does not leak from these connecting parts.
The liquid L is, for example, hydraulic oil.
The liquid L is filled into the hydraulic chamber 42 to a predetermined pressure.
The liquid L is injected into the hydraulic chamber 42 from the valve 48 .
For example, an injection pipe for injecting liquid L is connected to valve 48 . Then, the valve 48 is opened and the inside of the hydraulic chamber 42 is brought to negative pressure.
Thereafter, the liquid L is injected into the hydraulic pressure chamber 42, and when the liquid L reaches a predetermined pressure, the valve 48 is closed. In this way, the inside of the hydraulic chamber 42 is filled with the liquid L.

As described above, the pressure sensor 40 has a function of measuring the pressure of the liquid L filled inside the hydraulic pressure chamber 42. Moreover, the pressure sensor 40 has a function of wirelessly transmitting the measured output to the data processing device.

[About pressure measurement and torque measurement]
When torque is transmitted from one of the first shaft 16 or the second shaft 17 to the other and acts on the universal joint 10, stress corresponding to the torque acts on the yoke 13 through the bearing cup 12. The yoke 13 is slightly elastically deformed by this stress. At this time, the pressure of the liquid L in the hydraulic pressure chamber 42 provided in the first yoke 13a changes depending on the magnitude of the stress acting on the first yoke 13a. That is, the pressure of the liquid L within the hydraulic chamber 42 changes depending on the magnitude of the torque acting on the universal joint 10.
In particular, compressive stress acts on the keyway 23 of the yoke 13. This compressive stress is caused by the keyway 23 being pressed by the key 24, or by the key 24 being pressed by the keyway 23.
In this embodiment, the hydraulic chamber 42 is located between the keyway 23 and the fastening hole 28. Therefore, the hydraulic chamber 42 is located near the keyway 23. The compressive stress acts on the hydraulic chamber 42. Thereby, stress changes due to torque acting on the universal joint 10 appear as pressure changes in the liquid L.
Therefore, the torque acting on the universal joint 10 can be measured based on the output of the pressure sensor 40.

FIG. 5 is a block diagram showing a configuration example of the pressure sensor 40 and the data processing device.
In FIG. 5, the pressure sensor 40 can communicate wirelessly with the data processing device 50.
The pressure sensor 40 includes a communication section 40a and a sensor section 40b.
The sensor section 40b has a function of measuring the pressure of the liquid L in the hydraulic pressure chamber 42, and a function of providing an output indicating the measurement result to the communication section 40a.
The communication unit 40a has a function of performing wireless communication using a wireless WAN (Wide Area Network) or the like, and transmits and receives information to and from the data processing device 50 via the network. The communication unit 40a transmits an output indicating the measurement result to the data processing device 50.

The data processing device 50 includes a communication section 50a and a processing section 50b.
The communication unit 50a has a function of performing wireless communication with the communication unit 40a of the pressure sensor 40 and receiving an output indicating a measurement result transmitted from the pressure sensor 40.
The processing unit 50b is a computer having a CPU (Central Processing Unit) and a storage unit such as a memory or a hard disk.
The processing unit 50b has a function of determining the torque acting on the universal joint 10 based on the output indicating the measurement result.

The processing unit 50b stores a conversion table 50b1 in the storage unit.
Data indicating the correlation between the output from the pressure sensor 40 and the torque is registered in the conversion table 50b1. The conversion table 50b1 is created in advance using a testing device or the like, for example, before the universal joint 10 is attached to an actual machine. Data serving as a reference for the data showing the correlation is obtained by applying a known torque to the universal joint 10 using a testing device and measuring the pressure of the liquid L at that time. Different known torques are applied to the universal joint 10. The pressure of the liquid L when each of the different known torques is applied is measured by the pressure sensor 40. Data indicating the correlation between the output (measured pressure value) from the pressure sensor 40 and the torque is registered in the conversion table 50b1.
The output from the pressure sensor 40 is given to the processing section 50b. The processing unit 50b performs a process of converting the output from the pressure sensor 40 into a torque value using data indicating the correlation registered in the conversion table 50b1.
As described above, the universal joint 10 according to the embodiment can measure the torque acting on the universal joint 10.

As described above, according to the present embodiment, torque can be measured by measuring the pressure of the liquid L in the hydraulic pressure chamber 42. Therefore, the universal joint using a strain gauge can be used for torque measurement as described in the above problem. Compared to the above, a bridge circuit or the like is not required, and wiring etc. can be easily routed. As a result, the universal joint 10 according to this embodiment can measure torque with a simple configuration. Furthermore, in the universal joint 10 according to the present embodiment, the hydraulic pressure chamber is not destroyed by excessive torque that is instantaneously generated.
Further, in the universal joint 10 of this embodiment, as described above, the hydraulic chamber 42 is located between the bottom surface 23a and the second contact surface 30 in the axial direction, so that the fluid is reliably A pressure chamber 42 can be provided between the keyway 23 and the fastening hole 28.

Further, in the universal joint 10 of this embodiment, compressive stress acts on the step surface 23b of the keyway 23 along the circumferential direction. Therefore, in the universal joint 10 of this embodiment, compressive stress acts on the keyway 23 over the entire length of the keyway 23 .
In this regard, in the present embodiment, the hydraulic pressure chamber 42 includes the cylindrical hole 44 along the longitudinal direction of the keyway 23, so the universal joint 10 of the present embodiment has the hydraulic pressure chamber 42 and the keyway. 23 can be secured in a wide range along the longitudinal direction of the keyway 23. Thereby, the universal joint 10 according to the present embodiment can cause a pressure change in the liquid L caused by a stress change to occur more significantly.

〔others〕
The embodiments disclosed herein are illustrative in all respects and are not restrictive.
For example, in the embodiment described above, the hole 44 opens in the outer peripheral surface 13g of the first yoke 13a, and the pressure sensor 40 is fixed outside the bearing cup 12.
However, as shown in FIG. 6, the hole 44 may have a first cylindrical surface 44a and a second cylindrical portion 44c. The first cylindrical surface 44a shown in FIG. 6 does not have an opening on the outer peripheral surface 13g. The first cylindrical surface 44a has an opening formed in the outer peripheral surface 13g, and then the opening is closed by a plug or welding. Further, the second cylindrical portion 44c extends along the axial direction. The second cylindrical portion 44c is connected to the first cylindrical surface 44a and opens to the end surface 13t of the yoke 13 (second yoke 13b). Therefore, the second cylindrical portion 44c communicates the first cylindrical surface 44a with the outside.
An adapter 46 made of a single tube is connected to the open end of the second cylindrical portion 44c. A pressure sensor 40 is provided at the tip of the adapter 46.
In this case, the pressure sensor 40 is fixed to the outer peripheral surface of the second shaft 17.
In the case of the configuration shown in FIG. 6 as well, torque measurement is possible with a simple configuration, as in the case of the configuration of the above embodiment.

The scope of the present invention is not limited to the above-described embodiments, and includes all modifications within the scope of equivalents to the configurations described in the claims.

10 Universal joint 11 Cross shaft 11a Trunnion 12 Bearing cup 13 Yoke 13a First yoke 14 Fastening member 15 Roller 20 First surface 22 First contact surface 23 Keyway 23a Bottom surface 24 Key 25 Through hole 26 Second surface 28 Fastening hole 30 Second contact surface 40 Pressure sensor 42 Liquid pressure chamber L Liquid

Claims

a cross shaft having a trunnion;
a bearing cup that supports the trunnion via a plurality of rollers;
a yoke to which the bearing cup is attached;
a fastening member that fixes the bearing cup to the yoke;
A pressure sensor;
The bearing cup is
a first surface including a first contact surface that contacts the yoke and a key that projects with respect to the first contact surface;
a through hole that is open to the first contact surface and through which the fastening member passes;
The yoke is
a second surface that includes a second contact surface that contacts the first contact surface and a key groove that is recessed with respect to the second contact surface and into which the key is fitted;
a fastening hole opened in the second contact surface and into which the fastening member is fastened;
It has a hydraulic chamber filled with liquid,
the pressure sensor measures the pressure of the liquid;
A universal joint in which at least a portion of the hydraulic chamber is located between the keyway and the fastening hole.
The universal joint according to claim 1, wherein the hydraulic pressure chamber is located between the bottom surface of the keyway and the second contact surface in an axial direction parallel to the central axis of the universal joint.
The key and the keyway extend along a radial direction perpendicular to the central axis,
The universal joint according to claim 1, wherein the hydraulic chamber includes a cylindrical hole extending in the longitudinal direction of the keyway.