SNOWFLORENCE

Abstract

A universal joint 10 includes: a spider joint 11 including a pin 11a; a bearing shell 12 supporting the pin 11a via a plurality of rollers 15; a yoke 13 to which the bearing shell 12 is attached; a fastening member 14 fastening the bearing shell 12 to the yoke 13; and a pressure sensor 40. The bearing shell 12 includes: a first surface 20 including a first abutment surface 22 abutting the yoke 13 and a key 24 projecting with respect to the first abutment surface 22; and a through hole 25 opening toward the first abutment surface 22 and through which the fastening member 14 passes.The yoke 13 includes: a second surface 26 including a second abutment surface 30 abutting the first abutment surface 22, and a keyway 23 recessed with respect to the second abutment surface 30 and into which the key 24 is fitted; a mounting hole 28 opening onto the second abutment surface 30 and in which the mounting member 14 is mounted; and a hydraulic chamber 42 filled with a fluid L. The pressure sensor 40 measures the pressure of the fluid L. At least a portion of the hydraulic chamber 42 is located between the keyway 23 and the mounting hole 28.

Description

Technical area

[0001] The present disclosure relates to universal joints. State of the art State of the art

[0002] Patent Document 1 discloses a large universal joint used for a drive shaft of a rolling mill, etc. Prior art documentsPatent documents

[0003] Patent Document 1: Japanese Unexamined Patent Application Laid-Open No. 2006-77873 (JP 2006-77873 A) Summary of the inventionProblem solved by the invention

[0004] For example, to measure the torque acting on a drive shaft of a rolling mill that uses a universal joint, a strain gauge may be attached to the drive shaft. The torque acting on the drive shaft is measured based on the output of the strain gauge. However, torque measurement using a strain gauge requires connecting not only the strain gauge but also a transmitter for obtaining the strain gauge output during rotation of the drive shaft, a bridge circuit, etc. In addition, since a large number of cables must be laid to connect these devices, the device configuration for torque measurement is often relatively complicated. In addition, the strain gauge may be damaged by excessive torque generated temporarily.

[0005] The universal joint, which is connected to the drive shaft, contains a variety of parts.

[0006] The inventors of the present application focused on this point and thought that measuring the stress on one of the plurality of parts of the universal joint would make it possible to measure the torque on the drive shaft with a relatively simple configuration. The inventors thus arrived at an embodiment of the present disclosure. Means to solve the problem

[0007] A universal joint according to the embodiment includes: a spider joint including a pin; a bearing shell supporting the pin via a plurality of rollers; a yoke to which the bearing shell is attached; a fastening member fastening the bearing shell to the yoke; and a pressure sensor. The bearing shell includes: a first surface including a first abutment surface abutting against the yoke and a key projecting with respect to the first abutment surface; and a through hole opening toward the first abutment surface and through which the fastening member passes.The yoke includes: a second surface including a second abutment surface abutting the first abutment surface, and a keyway recessed with respect to the second abutment surface and into which the key is fitted; a mounting hole opening onto the second abutment surface and in which the mounting member is mounted; and a hydraulic chamber filled with a fluid. The pressure sensor measures a pressure of the fluid. At least a portion of the hydraulic chamber is located between the keyway and the mounting hole. Effects of the invention

[0008] According to the present disclosure, a universal joint that can measure torque with a simple configuration can be obtained. Short description of the characters Fig. 1 is a diagram showing a universal joint according to an embodiment. Fig. 2 is a perspective view of the components of the universal joint according to the embodiment. Fig. 3 is a partial sectional view along the line III-III in Fig. 1. Fig. 4 is a partial sectional view along the line IV-IV in Fig. 3. 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 modification. Modes for carrying out the invention

[0009] First, the contents of an embodiment are listed and described. Overview of the embodiment

[0010] (1) A universal joint according to the embodiment includes: a spider joint including a pin; a bearing shell supporting the pin via a plurality of rollers; a yoke to which the bearing shell is attached; a fastening member fastening the bearing shell to the yoke; and a pressure sensor. The bearing shell includes: a first surface including a first abutment surface abutting against the yoke and a key projecting with respect to the first abutment surface; and a through hole opening toward the first abutment surface and through which the fastening member passes.The yoke includes: a second surface including a second abutment surface abutting the first abutment surface, and a keyway recessed with respect to the second abutment surface and into which the key is fitted; a mounting hole opening onto the second abutment surface and in which the mounting member is mounted; and a hydraulic chamber filled with a fluid. The pressure sensor measures a pressure of the fluid. At least a portion of the hydraulic chamber is located between the keyway and the mounting hole.

[0011] When torque is applied to the universal joint via a drive shaft, etc., a stress corresponding to the torque acts on the yoke through the bearing shell. The yoke is slightly elastically deformed by this stress. At this time, the pressure of the fluid in the hydraulic chamber provided in the yoke changes according to the magnitude of the stress acting on the yoke. In other words, the pressure of the fluid in the hydraulic chamber changes according to the magnitude of the torque acting on the universal joint. Specifically, a 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 the embodiment, at least a part of the hydraulic chamber is located between the keyway and the mounting hole. Therefore, the hydraulic chamber is located close to the keyway.The compression stress acts on the hydraulic chamber. Therefore, a change in stress due to the torque acting on the universal joint appears as a change in the fluid pressure. Accordingly, the universal joint of the embodiment can measure the torque acting on the universal joint based on the output of the pressure sensor. As described above, the universal joint according to the embodiment can measure the torque by measuring the fluid pressure in the hydraulic chamber. This eliminates the need for a bridge circuit, etc., and simplifies a wire routing compared to those universal joints using a strain gauge for torque measurement, which was a problem described above. As a result, the universal joint of the embodiment can measure the torque with a simple configuration.In the universal joint of the embodiment, the hydraulic chamber is not destroyed by excessive torque temporarily generated.

[0012] (2) In the above universal joint, the hydraulic chamber is preferably located between a bottom surface of the keyway and the second abutment surface in an axial direction parallel to a center axis of the universal joint. In this case, the hydraulic chamber can be reliably provided between the keyway and the mounting hole.

[0013] (3) In the universal joint of the present embodiment, a compressive stress acts on the keyway in a circumferential direction. Therefore, in the universal joint of the embodiment, the compressive stress acts on the keyway along the entire length in a longitudinal direction of the keyway. In this regard, when the key and the keyway extend in a radial direction perpendicular to the central axis in the above universal joint, the hydraulic chamber preferably includes a tubular hole extending in the longitudinal direction of the keyway. This ensures that the hydraulic chamber and the keyway are close and adjacent to each other over a wide range in the longitudinal direction of the keyway in the universal joint of the embodiment. The universal joint of the embodiment can therefore cause a more noticeable change in the pressure of the fluid due to a change in stress. Details of the embodiment

[0014] In the following, a preferred embodiment is described with reference to the drawings. overall structure

[0015] Fig. 1 is a diagram showing a universal joint according to the embodiment. Fig. 2 is a perspective view of the individual parts of the universal joint according to the embodiment. This universal joint 10 is used, for example, for a rolling mill in a steel mill. Specifically, the universal joint 10 is arranged between an input shaft and a drive shaft of a rolling mill roll or between an output shaft and a drive shaft of a drive motor, connecting the pair of shafts in such a way that the pair of shafts can rotate together. The universal joint 10 transmits a rotational force from one of the shafts of the pair of shafts to the other.

[0016] The universal joint 10 includes a single spider joint 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 fastening the bearing cups 12 to the yokes 13. The plurality of fastening members 14 are, for example, bolts. The spider joint 11 has four pins 11a. Each bearing cup 12 supports or holds a corresponding pin 11a via a plurality of rollers 15. All bearing cups 12 have the same configuration. Each bearing cup 12 is attached to the pair of yokes 13.

[0017] The pair of yokes 13 is connected to a pair of shafts (not shown) of a rolling mill in such a way that the shaft pair can rotate together. Of the pair of yokes 13, a first yoke 13a, which is located on the right side in Fig. 1 and Fig. 2, is contained in a first shaft 16. The first yoke 13a can rotate with the first shaft 16. The first shaft 16 is connected to one of the shafts of the rolling mill shaft pair. Of the pair of yokes 13, a second yoke 13b is located on the left side in Fig. 1 and Fig. 2, is contained in a second shaft 17. The second yoke 13b can rotate with the second shaft 17. The second shaft 17 is connected to the other shaft of the rolling mill shaft pair. The first yoke 13a and the second yoke 13b have the same configuration.

[0018] In the state where the center axis of the first shaft 16 (first yoke 13a) and the center axis of the second shaft 17 (second yoke 13b) are arranged on the same straight line (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. The direction perpendicular to the central axis C is the "radial direction." The direction of rotation about the central axis C is the "circumferential direction."

[0019] As it is in Fig. 2, each bearing shell 12 has a first surface 20 facing the yoke 13 and a plurality of through holes 25. The first surface 20 includes a first abutment surface 22 abutting the yoke 13 and a key 24. The key 24 protrudes in a rectangular shape from the first abutment surface 22. The plurality of through holes 25 are provided parallel to the axial direction. The plurality of through holes 25 extend between the first surface 20 and a first opposing surface 19. The first opposing surface 19 is the surface of the bearing shell 12 facing the opposite side from the first surface 20. In the present embodiment, a total of six through holes 25 are provided, three on each side in the circumferential direction of the bearing shell 12.The plurality of through holes 25 open to two regions 22a of the first abutment surface 22, which are adjacent to both sides in the circumferential direction of the wedge 24. Three through holes 25 open to each of the two regions 22a.

[0020] Two pairs of bearing shells 12 are mounted on a pair of yokes 13, one pair on each yoke 13. The following description concerns the configuration of the first yoke 13a. On the other hand, the configuration of the second yoke 13b is the same as the configuration of the first yoke 13a. The first yoke 13a has a second surface 26 facing the first surface 20 of the bearing shell 12 and a plurality of mounting holes 28. The second surface 26 includes a pair of second abutment surfaces 30 and a pair of keyways 23. Each of the pair of second abutment surfaces 30 is a surface that abuts against the first abutment surface 22 of one of the pair of bearing shells 12. The pair of second abutment surfaces 30 is provided on both sides in the radial direction of the second surface 26 with the center axis C therebetween.

[0021] The pair of keyways 23 are recessed with respect to the pair of second abutment surfaces 30. The keys 24 of the pair of bearing shells 12 are fitted into the pair of keyways 23. Each of the keyways of the pair of keyways 23 extends from an outer peripheral surface 13g of the first yoke 13a in the radial direction. Therefore, the keyways 23 are provided by cutting the outer peripheral surface 13g.

[0022] The plurality of fastening holes 28 are provided in each of the pair of second abutment surfaces 30. The plurality of fastening holes 28 open to two regions 30a of the second abutment surface 30 adjacent to both sides in the circumferential direction of the keyway 23. Three fastening holes 28 open to each of the two regions 30a. The inner circumferential surfaces of the fastening holes 28 are threaded. External threads at distal ends of the fastening members 14 are screwed to these internal threads.

[0023] The fastening members 14 are inserted into the through holes 25 from the side of the first opposing surface 19 of the bearing shell 12 and screwed into the fastening holes 28. The bearing shell 12 is thus fastened to the second surface 26 of the first yoke 13a. At this time, the first contact surface 22 of the bearing shell 12 and the second contact surface 30 of the first yoke 13a abut each other.

[0024] The universal joint 10 of the present embodiment further includes a pressure sensor 40. The pressure sensor 40 measures the pressure of a fluid filling a hydraulic chamber 42 provided in the first yoke 13a. hydraulic chamber

[0025] The above hydraulic chamber 42 is installed on or in the first yoke 13a of the present embodiment.

[0026] Fig. 3 is a partial sectional view along the line III-III in Fig. 1. As it is in Fig. 3, the hydraulic chamber 42 is composed of a hole 44 and the interior of an adapter 46.

[0027] The hole 44 opens onto 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 in the longitudinal direction of the keyway 23. Fig. 4 is a partial sectional view along the line IV-IV in Fig. 3. In Fig. 4, the keyway 23 has a bottom surface 23a and a pair of step surfaces 23b. The pair of step surfaces 23b are surfaces connecting a pair of long sides of the bottom surface 23a and the two regions 30a on both sides of the keyway 23. As shown in Fig. 3 and Fig. 4, the hole 44 is provided between the keyway 23 and the mounting holes 28. Therefore, the hydraulic chamber 42 is located between the keyway 23 and the mounting holes 28. As shown in Fig. 4, the hole 44 is also provided between the bottom surface 23a of the keyway 23 and the region 30a (second abutment surface 30) in the axial direction. Therefore, the hydraulic chamber 42 is located between the bottom surface 23a and the second abutment surface 30 in the axial direction.

[0028] When a torque is transmitted between the wedge 24 and the keyway 23, the step surfaces 23b on the torque source side press the wedge 24. The wedge 24, which receives the torque, presses the step surface 23b. As a result, a compressive stress acts on a surface portion that has the step surface 23b as its surface, so that there is a region that undergoes slight plastic deformation. Therefore, in Fig. 4, the distance W between the step surface 23b and the hole 44 is set to such a value that no plastic deformation occurs in the hole 44. As a result, the plastic deformation occurring in the surface portion of the step surface 23b does not affect the hydraulic chamber 42.

[0029] As it is in Fig. 3, the adapter 46 is attached to an outer end 44a1 of the first cylindrical surface 44a. As shown in Fig. As can be seen in Figure 2, the adapter 46 is a T-joint. The adapter 46 includes a first tube 46a extending in the radial direction and a second tube 46b extending in the axial direction. The first tube 46a is connected to substantially the center in the longitudinal direction of the second tube 46b. The first tube 46a and the second tube 46b communicate with each other.

[0030] As it is in Fig. 3, a distal end 46a1 of the first tube 46a, which is directed inward in the radial direction, is press-fitted into the outer end 44a1.

[0031] As it is in Fig. As shown in Fig. 1, the pressure sensor 40 is provided at a distal end 46b1 of the second tube 46b facing the second yoke 13b. The pressure sensor 40 is fixed to the outside of the bearing shell 12. A valve 48 is provided at a distal end 46b2 of the second tube 46b facing the opposite direction to the distal end 46b1. The valve 48 can be opened and closed, and can be switched between the state in which the inside and outside of the hydraulic chamber 42 communicate with each other and the state in which the inside and outside of the hydraulic chamber 42 do not communicate with each other.

[0032] As it is in Fig. 3, the hydraulic chamber 42 is filled with a fluid L. A connecting portion between the hole 44 and the adapter 46, a connecting portion between the adapter 46 and the pressure sensor 40, and a connection between the adapter 46 and the valve 48 are sealed. The fluid L in the hydraulic chamber 42 does not leak from these connecting portions. The fluid L is, for example, hydraulic oil. The hydraulic chamber 42 is filled with the fluid L up to a predetermined pressure. The fluid L is injected into the hydraulic chamber 42 through the valve 48. For example, an injection pipe for injecting the fluid L is connected to the valve 48. The valve 48 is then opened to reduce the pressure in the hydraulic chamber 42 to a negative pressure. After that, the fluid L is injected into the hydraulic chamber 42. When the fluid L reaches the predetermined pressure, the valve 48 is closed.The hydraulic chamber 42 is thus filled with the liquid L.

[0033] As described above, the pressure sensor 40 has a function of measuring the pressure of the fluid L filling the hydraulic chamber 42. The pressure sensor 40 also has a function of wirelessly transmitting the measured output to a data processing device. Pressure measurement and torque measurement

[0034] When a torque is transmitted from one of the first shaft 16 and the second shaft 17 to the other and acts on the universal joint 10, a stress corresponding to the torque acts on the yokes 13 through the bearing shells 12. The yokes 13 are slightly elastically deformed by this stress. At this time, the pressure of the fluid L in the hydraulic chamber 42 provided in the first yoke 13a changes according to the magnitude of the stress acting on the first yoke 13a. In other words, the pressure of the fluid L in the hydraulic chamber 42 changes according to the magnitude of the torque acting on the universal joint 10. In particular, a compressive stress acts on the keyways 23 of the yokes 13. This compressive stress is caused by the keyways 23 being pressed by the keys 24 or by the keys 24 being pressed by the keyways 23.In the present embodiment, the hydraulic chamber 42 is located between the keyway 23 and the mounting holes 28. Therefore, the hydraulic chamber 42 is located near the keyway 23. The compression stress acts on the hydraulic chamber 42. Therefore, a change in the stress due to the torque acting on the universal joint 10 appears as a change in the pressure of the fluid L. Accordingly, the torque acting on the universal joint 10 can be measured based on the output of the pressure sensor 40.

[0035] Fig. 5 is a block diagram showing a configuration example of the pressure sensor 40 and the data processing device. Fig. 5, the pressure sensor 40 can communicate wirelessly with a data processing device 50. The pressure sensor 40 includes a communication unit 40a and a sensor unit 40b. The sensor unit 40b has a function of measuring the pressure of the fluid L in the hydraulic chamber 42 and a function of providing an output indicative of the measurement result to the communication unit 40a. The communication unit 40a has a function of performing wireless communication using a wireless WAN (Wide Area Network), etc., and sends and receives information to and from the data processing device 50 via a network. The communication unit 40a sends an output indicative of the measurement result to the data processing device 50.

[0036] The data processing device 50 includes a communication unit 50a and a processing unit 50b. The communication unit 50a has a function of wirelessly communicating with the communication unit 40a of the pressure sensor 40 to receive an output indicative of the measurement result sent from the pressure sensor 40. The processing unit 50b is a computer including a CPU (Central Processing Unit) and a storage unit such as a memory and a hard disk. The processing unit 50b has a function of obtaining a torque acting on the universal joint 10 based on the output indicative of the measurement result.

[0037] The processing unit 50b stores a conversion table 50b1 in the storage unit. Data showing a correlation between the output from the pressure sensor 40 and the torque is registered in the conversion table 50b1. For example, the conversion table 50b1 is created in advance using a test jig, etc., before the universal joint 10 is mounted on an actual machine. Reference data for the data showing the correlation is obtained by applying a known torque to the universal joint 10 by the test jig and measuring the pressure of the fluid L at that time. Different known torques are applied to the universal joint 10. The pressure of the fluid L when each of the different known torques is applied is measured by the pressure sensor 40.Data showing a correlation between the output from the pressure sensor 40 (measured pressure value) and the torque are registered in the conversion table 50b1. The output from the pressure sensor 40 is provided to the processing unit 50b. The processing unit 50b performs a process of converting the output from the pressure sensor 40 into a torque value by using the data showing the correlation registered in the conversion table 50b1. In this way, the universal joint 10 according to the embodiment can measure the torque acting on the universal joint 10.

[0038] According to the present embodiment, torque can be measured by measuring the pressure of the fluid L in the hydraulic chamber 42. This eliminates the need for a bridge circuit, etc., and simplifies a wire routing compared to those universal joints using a strain gauge for torque measurement, as described above as a problem. As a result, the universal joint 10 of the present embodiment can measure torque with a simple configuration. In the universal joint 10 of the present embodiment, the hydraulic chamber is not destroyed by excessive torque temporarily generated. In the universal joint 10 of the present embodiment, as described above, the hydraulic chamber 42 is located between the bottom surface 23a and the second abutment surface 30 in the axial direction.Therefore, the hydraulic chamber 42 can be reliably provided between the keyway 23 and the mounting holes 28.

[0039] In the universal joint 10 of the present embodiment, a compressive stress in the circumferential direction acts on the stepped surface 23b of the keyway 23. Therefore, in the universal joint 10 of the present embodiment, the compressive stress acts on the keyway 23 along the entire length in the longitudinal direction of the keyway 23. In this regard, in the present embodiment, the hydraulic chamber 42 includes the tubular hole 44 extending in the longitudinal direction of the keyway 23. This ensures that the hydraulic chamber 42 and the keyway 23 are close and adjacent to each other over a wide range in the longitudinal direction of the keyway 23 in the universal joint 10 of the present embodiment. Therefore, the universal joint 10 of the present embodiment can cause a more noticeable change in the pressure of the fluid L due to a change in the stress. Other

[0040] The embodiment disclosed herein is illustrative and not restrictive in all respects. For example, in the above embodiment, the hole 44 opens to the outer peripheral surface 13g of the first yoke 13a, and the pressure sensor 40 is attached to the outside of the bearing shell 12. However, as shown in Fig. 6, the hole 44 may have the first cylindrical surface 44a and a second cylindrical portion 44c. Fig. The first cylindrical surface 44a shown in FIG. 6 has no opening in the outer peripheral surface 13g. After an opening of the first cylindrical surface 44a is formed in the outer peripheral surface 13g, this opening is closed by a plug or by welding. The second cylindrical portion 44c extends in the axial direction. The second cylindrical portion 44c connects to the first cylindrical surface 44a and opens to an end surface 13t of the yoke 13 (second yoke 13b). Therefore, the second cylindrical portion 44c allows the first cylindrical surface 44a to communicate with the outside. The adapter 46, which is a single tube, is connected to an open end of the second cylindrical portion 44c. The pressure sensor 40 is provided at a distal end 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, which is also in Fig. 6, the torque can be measured with a simple configuration as in the case of the configuration of the above embodiment.

[0041] The scope of the present invention is not limited to the above embodiment and is intended to include all modifications within the scope corresponding to that of the configurations described in the claims. Description of reference symbols

[0042] 10 ... universal joint, 11 ... spider joint or joint star, 11a ... pin, 12 ... bearing shell, 13 ... yoke, 13a ... first yoke, 14 ... fastening link, 15 ... roller, 20 ... first surface, 22 ... first contact surface, 23 ... keyway, 23a ... base surface, 24 ... key, 25 ... through hole, 26 ... second surface, 28 ... fastening hole, 30 ... second contact surface, 40 ... pressure sensor, 42 ... hydraulic chamber, L ... fluid QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2006-77873

[0003] JP 2006-77873 A

[0003]

Claims

[1] Cardan joint which has: a spider joint containing a pivot; a bearing shell that supports the journal via a plurality of rollers; a yoke to which the bearing shell is attached; a fastening member that secures the bearing shell to the yoke; and a pressure sensor, where the bearing shell contains: a first surface including a first bearing surface abutting the yoke and a wedge projecting relative to the first bearing surface, and a through hole opening onto the first contact surface and through which the fastening member passes, the yoke contains: a second surface including a second bearing surface abutting the first bearing surface, and a keyway recessed with respect to the second bearing surface and into which the key is fitted, a fastening hole opening onto the second contact surface and in which the fastening member is fastened, and a hydraulic chamber filled with a liquid, the pressure sensor measures a pressure of the fluid, and at least a part of the hydraulic chamber is located between the keyway and the mounting hole. [2] The universal joint according to claim 1, wherein the hydraulic chamber is located between a bottom surface of the keyway and the second abutment surface in an axial direction parallel to a center axis of the universal joint. [3] Universal joint according to claim 1, wherein: the key and the keyway extend in a radial direction perpendicular to the central axis; and the hydraulic chamber contains a tubular hole extending in a longitudinal direction of the keyway.

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