Rotating device

Abstract

To provide a rotary device that enables reduction of the weights of rotary bodies without lowering hysteresis torque.SOLUTION: The rotary device includes a first rotary body, a second rotary body, and a viscous fluid. The second rotary body is arranged at a space from the first rotary body. The second rotary body is arranged rotatably relative to the first rotary body. The viscous fluid is arranged in a space between the first rotary body and the second rotary body. The second rotary body has a first surface opposed to the first rotary body and a second surface not opposed to the first rotary body. The second rotary body has a punched part in the second surface.SELECTED DRAWING: Figure 7B

Description

Technical Field

[0001] The present invention relates to a rotating device.

Background Art

[0002] Conventionally, in vehicles such as automobiles, as a rotating device that is attached to an engine and effectively attenuates rotational fluctuations of the engine, for example, a dual mass flywheel (DMF) is known. In a DMF, resonance may occur at engine startup. As a result, excessive resonance torque may be input to the DMF, which may cause generation of abnormal noise and deterioration of the durability of various components. Therefore, under conditions where the DMF resonates and excessive torque is generated, it is necessary to generate hysteresis torque to prevent damage to the DMF. Thus, in the damper device of Patent Document 1, hysteresis torque is generated depending on the torsional angle between members.

[0003] The DMF of Patent Document 1 has an input-side rotating member to which engine power is input, and an output plate rotatably arranged with respect to the input-side rotating member. The input-side rotating member and the output plate are elastically connected in the circumferential direction by a plurality of springs. Also, spring sheets are arranged between each flywheel and the spring, and between each spring.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a rotating device in which a first rotating body and a second rotating body rotate relative to each other, as described above, there is a need to reduce the weight of the second rotating body. In this invention, the goal is to reduce the weight of the second rotating body, using a spring seat as an example. However, simply removing material from the second rotating body can sometimes lead to a decrease in hysteresis torque. Therefore, the objective of this invention is to provide a rotating device that can reduce the weight of the rotating body without reducing the hysteresis torque. [Means for solving the problem]

[0006] (1) The rotating device according to the present invention comprises a first rotating body, a second rotating body, and a viscous fluid. The second rotating body is positioned with a gap between it and the first rotating body. The second rotating body is positioned to be rotatable relative to the first rotating body. The viscous fluid is positioned in the gap between the first rotating body and the second rotating body. The second rotating body has a first surface facing the first rotating body and a second surface that does not face the first rotating body. The second rotating body has a weight-reducing portion on its second surface.

[0007] The inventors have discovered that the shear torque of the grease generated during the operation of the rotating device in the gap between the first and second rotating bodies can be used as hysteresis torque. They have also discovered that the magnitude of the hysteresis torque is proportional to the area in contact with the viscous fluid on the surface of the second rotating body facing the first rotating body. Therefore, in the rotating device according to the present invention, the second surface of the second rotating body, which is one of the two surfaces (first surface facing the first rotating body and second surface not facing the first rotating body), is configured to have a weight-reducing portion. Since the second surface does not contribute to the generation of hysteresis torque, the hysteresis torque does not decrease. For this reason, the weight of the second rotating body can be reduced without reducing the hysteresis torque.

[0008] (2) Preferably, the rotating device further comprises an elastic member. The elastic member is arranged adjacent to the second rotating body in the circumferential direction. The second rotating body has a housing portion on a surface facing the circumferential direction. The housing portion houses the elastic member. The opening area of ​​the weight-reducing portion is smaller than the opening area of ​​the housing portion.

[0009] (3) Preferably, the second rotating body has a circumferential surface facing the circumferential direction. The weight-reducing portion is located on the circumferential surface of the second rotating body.

[0010] (4) Preferably, the weight-reducing portion is a recess that opens in the circumferential direction.

[0011] (5) Preferably, the weight-reducing portion is positioned radially outward or radially inward relative to the housing portion.

[0012] (6) Preferably, the weight-reducing portion has a first weight-reducing portion and a second weight-reducing portion. The first weight-reducing portion is located radially outward relative to the housing portion. The second weight-reducing portion is located radially inward relative to the housing portion. The first weight-reducing portion is larger than the second weight-reducing portion.

[0013] (7) Preferably, the viscous fluid is placed in the first hollowed-out section but not in the second hollowed-out section. [Effects of the Invention]

[0014] As described above, the present invention provides a rotating device that can reduce the weight of the rotating body without reducing the hysteresis torque. [Brief explanation of the drawing]

[0015] [Figure 1] Cross-sectional view of a rotating device according to one embodiment of the present invention. [Figure 2] Front view of the rotating device shown in Figure 1. [Figure 3] Front view of the input section. [Figure 4] A partial cross-sectional perspective view of the rotating device from the radially outer side. [Figure 5] A schematic diagram illustrating the location of the grease. [Figure 6] A magnified view of a portion of Figure 1. [Figure 7A] Side view of an end-piece spring seat. [Figure 7B] Front view of the end spring seat. [Figure 8]Side view of the intermediate spring sheet. [Figure 9A] Side view of the end spring sheet in the modified example. [Figure 9B] Front view of the end spring sheet in the modified example. [Figure 10A] Side view of the end spring sheet in a modified example different from FIG. 9A. [Figure 10B] Front view of the end spring sheet in a modified example different from FIG. 9B. [Figure 11A] Side view of the end spring sheet in a modified example different from FIGS. 9A and 10A. [Figure 11B] Front view of the end spring sheet in a modified example different from FIGS. 9B and 10B. [Figure 12] Diagram showing the relationship between the viscosity index and the rate of increase in hysteresis torque.

Mode for Carrying Out the Invention

[0016] [Overall Configuration] FIG. 1 is a cross-sectional view of a dual mass flywheel 100 (an example of a rotating device, hereinafter simply referred to as "DMF100") according to an embodiment of the present invention. Further, FIG. 2 is a front view of DMF100, showing a part of the member (for example, the left half of the secondary flywheel 5, etc.) removed. In FIG. 1, the line O-O is the rotation axis O. In FIG. 1, an engine is arranged on the left side of DMF100, and a drive unit including an electric motor, a transmission, etc. is arranged on the right side.

[0017] In the following description, the axial direction is the direction in which the rotation axis O of DMF100 extends. The left side of FIG. 1 is defined as the "first axial side", and the right side of FIG. 1 is defined as the "second axial side". Also, the circumferential direction is the circumferential direction of a circle centered on the rotation axis O, and the radial direction is the radial direction of a circle centered on the rotation axis O.

[0018] The DMF100 is a device installed between the crankshaft of an engine (an example of a component on the drive source side) and the input shaft of a drive unit, and is used to dampen rotational fluctuations. The DMF100 has a primary flywheel 2 (an example of a first rotating body), a plurality of spring seats 3, and grease 4 (an example of a viscous fluid). The DMF100 further has a plurality of damper sections 40 and a secondary flywheel 5.

[0019] [Primary Flywheel 2] As shown in Figure 1, the primary flywheel 2 receives power from the engine. The primary flywheel 2 is fixed to an engine component, such as the crankshaft (not shown).

[0020] The primary flywheel 2 is rotatably positioned around the rotation axis O. The primary flywheel 2 includes an input plate 21 (an example of a first input section), a seal plate 22 (an example of a second input section), and a support member 23.

[0021] The input plate 21 is held between the crankshaft and the support member 23 and fixed to the crankshaft by bolts.

[0022] As shown in Figures 1 and 2, the input plate 21 has a first main body portion 21a and a cylindrical portion 21b. The first main body portion 21a is configured to be rotatable about the rotation axis O. The first main body portion 21a is substantially formed in the shape of a disc.

[0023] As shown in Figure 3, the first main body portion 21a has an inner circumference portion 21h and an outer circumference portion 21e. The outer circumference portion 21e is positioned on the first axial side relative to the inner circumference portion 21h of the first main body portion 21a (see Figure 1).

[0024] Furthermore, the first main body portion 21a has a plurality (for example, two) of first contact portions 21f. Each first contact portion 21f is a portion that contacts the damper portion 40 in the circumferential direction. Each first contact portion 21f is provided on the outer periphery portion 21e of the first main body portion 21a. Each first contact portion 21f extends radially along the outer periphery portion 21e. Each first contact portion 21f protrudes to the second side in the axial direction (see Figure 1).

[0025] As shown in Figures 1 and 2, the cylindrical portion 21b is cylindrical in shape and extends in the axial direction. The cylindrical portion 21b extends from the outer peripheral end of the first main body portion 21a to the second side in the axial direction. The cylindrical portion 21b is formed integrally with the first main body portion 21a.

[0026] The seal plate 22 is configured to rotate integrally with the input plate 21. For example, the seal plate 22 is fixed to the cylindrical portion 21b by fixing means, such as welding.

[0027] The seal plate 22 is rotatably positioned around the axis of rotation O. The seal plate 22 is substantially annular in shape.

[0028] The seal plate 22 is positioned at a distance from the first main body 21a in the axial direction. A spring seat 3 is positioned between the seal plate 22 and the first main body 21a in the axial direction.

[0029] The seal plate 22 has a plurality (for example, two) second contact portions 22d. Each second contact portion 22d is a portion that contacts the damper portion 40 in the circumferential direction. Each second contact portion 22d is positioned opposite each first contact portion 21f in the axial direction, with a gap between them.

[0030] As shown in Figure 4, the seal plate 22 has an aperture portion 22j. The aperture portion 22j is formed on the axially second side surface of the second contact portion 22d. The aperture portion 22j is a recess that opens to the axially second side. The bottom of the aperture portion 22j may protrude to the axially first side on the second contact portion 22d. The aperture portion 22j may be formed on the axially first side surface of the first contact portion 21f. In this case, the aperture portion 22j is a recess that opens to the axially first side.

[0031] The support member 23 is a member that supports the input plate 21 and the seal plate 22. The support member 23 supports the input plate 21 so that it can rotate integrally with the input plate 21. The support member 23 also supports the seal plate 22 so that it can rotate integrally with the seal plate 22.

[0032] The support member 23 is configured to be rotatable around the rotation axis O. The support member 23 is substantially cylindrical in shape.

[0033] [Secondary flywheel 5] The secondary flywheel 5 transmits the power transmitted from the primary flywheel 2 to the damper section 40 to the output-side component.

[0034] The secondary flywheel 5 is rotatably positioned around the rotation axis O of the primary flywheel 2. The secondary flywheel 5 is rotatable relative to the primary flywheel 2. In detail, the secondary flywheel 5 is rotatably supported on the support member 23 of the primary flywheel 2 via a bearing 39.

[0035] The secondary flywheel 5 includes a first output member 51 and a second output member 52. The first output member 51 is configured to rotate integrally with the second output member 52. The first output member 51 is fixed to the second output member 52.

[0036] The first output member 51 has a second main body 51a and a plurality (for example, two) power transmission units 51b.

[0037] The second main body portion 51a is substantially annular in shape. The second main body portion 51a is fixed to the inner circumference of the second output member 52 by rivets.

[0038] The power transmitted from the engine to the primary flywheel 2 is transmitted to the multiple power transmission units 51b via the damper units 40. Each power transmission unit 51b extends radially outward from the second main body 51a. The power transmission units 51b are spaced apart from each other in the circumferential direction.

[0039] Each power transmission unit 51b is positioned between the first main body 21a and the seal plate 22 of the primary flywheel 2 in the axial direction. More specifically, as shown in Figure 4, each power transmission unit 51b is positioned with a fourth gap 84 between it and the first contact portion 21f of the primary flywheel 2 in the axial direction.

[0040] Each power transmission section 51b is rotatable relative to each first contact section 21f and each second contact section 22d in the axial direction between each first contact section 21f and each second contact section 22d.

[0041] The second output member 52 is positioned in the axial direction between the transmission and the damper portion 40. More specifically, the second output member 52 is positioned in the axial direction between the transmission and the seal plate 22.

[0042] [Damper Section 40] As shown in Figures 1 and 2, the damper section 40 elastically connects the primary flywheel 2 and the secondary flywheel 5. More specifically, the damper section 40 elastically connects the primary flywheel 2 and the secondary flywheel 5 in the circumferential direction.

[0043] In this embodiment, there is a pair of damper sections 40. In Figure 2, only one of the pair of damper sections 40 is shown.

[0044] Each damper section 40 is positioned radially inward of the cylindrical section 21b. Each damper section 40 is positioned between the first main body section 21a of the input plate 21 and the secondary flywheel 5 in the axial direction.

[0045] Each damper section 40 has a plurality (for example, 5) spring seats 3 and a plurality (for example, 4) coil springs 41.

[0046] [Spring Seat 3] The spring seat 3 is positioned to be rotatable relative to the primary flywheel 2. The spring seat 3 is positioned with a gap between it and the primary flywheel 2. In detail, the spring seat 3 is positioned axially between the input plate 21 and the seal plate 22. The spring seat 3 is positioned with a gap between it and the axial second side surface of the first body portion 21a, the inner circumferential surface of the cylindrical portion 21b, and the axial first side surface of the seal plate 22.

[0047] As shown in Figures 5 and 6, there is a first gap 81 between the input plate 21 and the spring seat 3. There is a second gap 82 between the seal plate 22 and the spring seat 3. More specifically, there is a first gap 81 in the axial direction between the first axial side surface of the spring seat 3 and the second side surface of the first main body portion 21a. There is a second gap 82 in the axial direction between the second axial side surface of the spring seat 3 and the first axial side surface of the seal plate 22. There is a third gap 83 in the radial direction between the outer circumferential surface of the spring seat 3 and the inner circumferential surface of the cylindrical portion 21b.

[0048] The spring seat 3 is positioned to be rotatable relative to the primary flywheel 2.

[0049] As shown in Figure 2, the spring seat 3 includes first and second end spring seats 3a and 3e, and first to third intermediate spring seats 3b, 3c, and 3d. The first end spring seat 3a corresponds to the second rotating body of the present invention. Since the second end spring seat 3e has the same shape as the first end spring seat 3a, and the second intermediate spring seat 3c and third intermediate spring seat 3d have the same shape as the first intermediate spring seat 3b, a detailed explanation of these will be omitted.

[0050] As shown in Figures 7A and 7B, the first end spring seat 3a has an inner circumference 34a, an outer circumference 34c, two side surfaces 34d, a bottom 34e, and a weight-reducing section 35. The inner circumference 34a, outer circumference 34c, and side surfaces 34d extend from the bottom 34e to one side in the circumferential direction. The inner circumference 34a, outer circumference 34c, two side surfaces 34d, and bottom 34e define a housing section 36. The housing section 36 is located on the circumferential surface 34W of the first end spring seat 3a facing the circumferential direction. The housing section 36 extends in the circumferential direction and opens to one side in the circumferential direction.

[0051] The first end spring seat 3a has a first surface F1 and a second surface F2. The first surface F1 is the surface facing the primary flywheel 2. That is, the first surface F1 includes the outer surface 34X and two side surfaces 34Y of the first end spring seat 3a. The second surface F2 is the surface not facing the primary flywheel 2. That is, the second surface F2 includes the circumferential surface 34W and the inner surface 34Z.

[0052] The weight-reducing section 35 is located on the second surface F2. More specifically, the weight-reducing section 35 is located on the circumferential surface 34W. The weight-reducing section 35 is a recess that opens in the circumferential direction. The weight-reducing section 35 opens in a circular shape. The depth of the weight-reducing section 35 is set to a depth that provides the amount necessary for weight reduction. For example, the depth of the weight-reducing section 35 can be the same as the depth of the housing section 36. The weight-reducing section 35 extends circumferentially parallel to the housing section 36. The weight-reducing section 35 may also be a through hole that penetrates in the circumferential direction. The weight-reducing section 35 is located radially outward from the housing section 36. Two weight-reducing sections 35 are provided.

[0053] The opening area of ​​the weight-reducing section 35 is smaller than the opening area of ​​the housing section 36. Here, the opening area refers to the area of ​​the opening of the weight-reducing section 35 or the housing section 36.

[0054] As shown in Figure 8, the first intermediate spring seat 3b has a shape in which the bottoms 34e of the two first end spring seats 3a are butted together and arranged in the circumferential direction. Therefore, a detailed explanation of the first intermediate spring seat 3b is omitted.

[0055] Each damper section 40 contains multiple coil springs 41 (for example, four), each arranged so as to be adjacent to the spring seat 3 in the circumferential direction. Each of the multiple coil springs 41 is arranged so as to act in series with each other between the primary flywheel 2 and the secondary flywheel 5. Each of the multiple coil springs 41 is located in a region defined by the axial second side surface of the first main body section 21a, the inner circumferential surface of the cylindrical section 21b, and the axial first side surface of the seal plate 22.

[0056] Multiple coil springs 41 contained in each damper section 40 are pressed against the power transmission section 51b and the first contact section 21f and second contact section 22d in the circumferential direction via the spring seat 3. In this way, the multiple coil springs 41 expand and contract between the power transmission section 51b and the first contact section 21f and second contact section 22d.

[0057] Each of the multiple (e.g., five) spring seats 3 included in each damper section 40 is positioned at the end of each coil spring 41 and supports the end of each coil spring 41. More specifically, the end of each coil spring 41 is housed in a housing section 36. The opening area of ​​the housing section 36 is larger than the opening area of ​​the weight-reducing section 35. Therefore, the weight-reducing section 35 cannot accommodate the end of the coil spring 41, but the housing section 36 can.

[0058] Here, the first to third intermediate spring seats 3b, 3c, and 3d included in each damper section 40 are positioned between adjacent coil springs 41 in the circumferential direction and support the ends of each coil spring 41. In addition, the first and second end spring seats 3a and 3e support the ends of the coil springs 41 adjacent to the power transmission section 51b in the circumferential direction.

[0059] Each of the first and second end spring seats 3a and 3e is in circumferential contact with the power transmission section 51b, the first contact section 21f, and the second contact section 22d, respectively. When the DMF 100 is activated, one of the first and second end spring seats 3a and 3e is pressed by the primary flywheel 2. The other of the first and second end spring seats 3a and 3e is pressed in the circumferential direction by the first output member 51. In this way, the multiple coil springs 41 expand and contract between the first output member 51 and the primary flywheel 2 via the spring seats 3.

[0060] [Grease 4] As shown in Figures 5 and 6, the grease 4 is placed in the gap between the primary flywheel 2 and the spring seat 3. More specifically, the grease 4 is placed in the first gap 81 between the input plate 21 and the spring seat 3, and in the second gap 82 between the seal plate 22 and the spring seat 3. The grease 4 is also placed in the third gap 83 between the inner circumferential surface of the cylindrical portion 21b and the outer circumferential surface of the spring seat 3.

[0061] In detail, the grease 4 is filled into the area defined by the second axial side surface of the first main body 21a, the inner circumferential surface of the cylindrical portion 21b, and the first axial side surface of the seal plate 22. When the DMF 100 is in operation, the grease 4 is received by the inner circumferential surface of the cylindrical portion 21b and spreads around the entire circumference of the cylindrical portion 21b by centrifugal force. When the DMF 100 is in operation, the grease 4 is filled to fill the first axial gap 81 between the spring seat 3 and the seal plate 22, the second axial gap 82 between the first main body 21a and the spring seat 3, and the third radial gap 83 between the spring seat 3 and the cylindrical portion 21b. When the DMF 100 is in operation, the inner circumferential portions of the first gap 81 and the second gap 82 do not need to be filled with grease 4. When the DMF 100 is in operation, the third gap 83 is completely filled with grease 4.

[0062] The grease 4 further contacts the first surface F1 of the spring seat 3. More specifically, the grease 4 is filled so as to cover the entire outer surface 34X of the spring seat 3. The grease 4 may also be filled so as to cover the entire or partially cover two sides 34Y of the spring seat 3.

[0063] The grease 4 does not come into contact with the second surface F2 of the spring seat 3. More specifically, it is filled so as not to come into contact with the inner surface 34Z of the spring seat 3.

[0064] The grease 4 is filled so that it may cover the entire surface of the spring seat 3 that comes into contact with the coil spring 41, or it may cover only a portion of it.

[0065] The grease 4 is also filled into the fourth axial gap 84 between the first contact portion 21f and the power transmission portion 51b, and the fifth axial gap 85 between the power transmission portion 51b and the second contact portion 22d.

[0066] Grease 4 generates hysteresis torque T. Specifically, when the DMF100 is in operation, the spring seat 3 rotates relative to the primary flywheel 2. This relative rotation shears the grease 4, generating a shear torque in the grease 4. This shear torque of the grease 4 is used as the hysteresis torque T.

[0067] Hysteresis torque T occurs in the first gap 81, the second gap 82, and the third gap 83. The hysteresis torque T that occurs in the first gap 81 will be described below. The total hysteresis torque obtained from the first end spring seat 3a is the sum of the hysteresis torques T calculated for each of the first gap 81, the second gap 82, and the third gap 83.

[0068] The hysteresis torque T is proportional to the characteristic radius R of the grease 4, the area A of the grease 4 in contact with the spring seat 3, the apparent viscosity η of the grease 4, and the relative angular velocity ω between the primary flywheel 2 and the spring seat 3. Furthermore, the hysteresis torque T is inversely proportional to the axial dimension H of the gap between the primary flywheel 2 and the spring seat 3. In other words, the hysteresis torque T is defined by the following equation (1). Equation (1) allows us to define the hysteresis torque T generated by the grease 4 in contact with one spring seat 3.

[0069]

number

[0070] The representative radius R is the representative radius of the grease 4 when the DMF100 is in operation. Specifically, when the DMF100 is in operation, the grease 4 is subjected to centrifugal force and spreads radially outward within the region defined by the axial second side surface of the first main body 21a, the inner circumferential surface of the cylindrical part 21b, and the axial first side surface of the seal plate 22. In other words, when the DMF100 is in operation, the grease 4 is in contact with the axial second side surface of the first main body 21a, the inner circumferential surface of the cylindrical part 21b, the axial first side surface of the seal plate 22, the axial first side surface of the spring seat 3, the outer circumferential surface of the spring seat 3, and the axial second side surface of the spring seat 3. The representative radius of the grease 4 at this time is R. The representative radius R is defined by the following equation (2) using the minimum grease radius R1 and the maximum grease radius R2 during operation. The maximum grease radius R2 is the distance from the rotation axis O to the outer surface 34X.

[0071]

number

[0072] Area A is the area of ​​grease 4 in contact with each surface of the spring seat 3 when the DMF 100 is in operation in the first gap 81.

[0073] The relative angular velocity ω is the relative angular velocity between the primary flywheel 2 and the spring seat 3 when the DMF100 is in operation.

[0074] Dimension H is the axial dimension of the gap between the primary flywheel 2 and the spring seat 3 when the DMF100 is in operation. In other words, for the first gap 81, dimension H is the axial dimension H1 of the first gap 81.

[0075] The hysteresis torque T generated in the second gap 82 and the third gap 83 can be calculated in the same way as the hysteresis torque T generated in the first gap 81. The differences between the hysteresis torque T obtained in the third gap 83 and the hysteresis torque T obtained in the first gap 81 are explained below.

[0076] In the third gap 83, the representative radius R is the distance from the axis of rotation O to the outer surface 34X, i.e., the maximum grease radius R2. Also, in the third gap 83, the area A is the area of ​​the grease 4 that is in contact with the outer surface 34X of the spring seat 3 when the DMF100 is in operation. In the third gap 83, the dimension H is the radial dimension H3 of the third gap 83.

[0077] The apparent viscosity η is the apparent viscosity of grease 4 when the DMF100 is in operation. The apparent viscosity η is defined by the following equation (3).

[0078]

number

[0079] In equation (3), μ is the well-known viscosity coefficient of grease 4.

[0080] n is the viscosity index of grease 4. The viscosity index n is calculated from the relationship between the shear rate of grease 4 and the apparent viscosity of grease 4. Specifically, the viscosity index n is calculated by varying the shear rate conditions of grease 4 at 24°C and measuring the apparent viscosity η of grease 4 using a capillary rheometer. The logarithm of the shear rate of grease 4 is plotted on the x-axis and the logarithm of the apparent viscosity of grease 4 is plotted on the y-axis, and the obtained results are plotted on a graph. A regression line is found for multiple plots. The regression line can be found using a well-known method. For example, the regression line may be found using the least squares method or by other methods. The viscosity index n of grease 4 is taken as the value obtained by adding 1 to the slope of the obtained line.

[0081] The viscosity index n is 0.4 or greater. The reason for this is as follows: From equations (1) and (3), the hysteresis torque T can be defined by the following equation (4).

number

[0082] Generally, the relative angular velocity (hereinafter simply referred to as relative angular velocity) between the primary flywheel 2 and the secondary flywheel 5 when resonance occurs during engine startup is considered to be approximately 40 times the relative angular velocity during normal operation. Normal operation refers to the period when the rotational speed is stable above a certain value. On the other hand, the fluctuation range of the damper input torque when resonance occurs during engine startup is approximately 5 times the fluctuation range of the damper input torque during normal operation. The rate of increase in the relative angular velocity and damper input torque fluctuation range between engine startup and normal operation remains similar even if the size of the DMF100 changes. Therefore, if a hysteresis torque T of 5 times or more than the hysteresis torque T required during normal operation is generated when the relative angular velocity changes 40 times, the resonance that occurs during engine startup can be sufficiently suppressed.

[0083] According to equation (4), the rate of increase of hysteresis torque T with respect to relative angular velocity is greatly influenced by the viscosity index n. Therefore, as shown in the embodiment described below, the relationship between the viscosity index n and the rate of hysteresis torque fluctuation was investigated. As a result, it was found that if the viscosity index n is 0.4 or higher, the rate of increase of hysteresis torque can be increased by 5 times or more. Therefore, the viscosity index n is 0.4 or higher. Conventional DMFs generally used have a viscosity index n of around 0.2. In this embodiment, since the viscosity index n is significantly higher than that of conventional greases, for example, to 0.4 or higher, resonance that occurs when the engine starts can be sufficiently suppressed.

[0084] Although the spring seat 3 and the coil spring 41 rotate relative to each other, the relative speed of the two members and the area in contact with the grease 4 are significantly smaller compared to the other first gap 81, second gap 82, and third gap 83. Therefore, the surface of the spring seat 3 that contacts the coil spring 41 does not contribute to the generation of hysteresis torque T.

[0085] The total hysteresis torque obtained for the entire DMF100 is the sum of the hysteresis torques T calculated for each of the first and second end spring seats 3a and 3e, and the first to third intermediate spring seats b to d.

[0086] Furthermore, the shear torque of the grease 4 can also be generated by the relative rotation between the primary flywheel 2 and the secondary flywheel 5. In this case, the shear torque of the grease 4 generated in the fourth gap 84 between the first contact portion 21f and the power transmission portion 51b, and the fifth gap 85 between the power transmission portion 51b and the second contact portion 22d, can also be used as the hysteresis torque T.

[0087] [Action / Effect] The torque transmitted from the engine to the primary flywheel 2 is input to the damper section 40. In the damper section 40, the torque is input to the input plate 21, and this torque is transmitted via the coil spring 41 to the output side electric motor, generator, transmission, etc.

[0088] Furthermore, for example, when starting the engine, resonance may occur due to the large inertia of the output side, resulting in excessive torque being input to the damper section 40. In such cases, it is necessary to generate hysteresis torque T. On the other hand, when driving, it is necessary to reduce the hysteresis torque T.

[0089] In this embodiment, the weight-reducing portion 35 is located on the second surface F2 of the spring seat 3, which does not face the primary flywheel 2, and the first surface F1 that faces the primary flywheel 2. As shown in equation (1), the magnitude of the hysteresis torque T is proportional to the area in contact with the grease 4 on the surface of the spring seat 3 that faces the primary flywheel 2. Since the weight-reducing portion 35 is not located on the first surface F1 where the hysteresis torque T is generated, the hysteresis torque T is not reduced. Therefore, the second rotating body can be made lighter without reducing the hysteresis torque T on the first surface F1. On the other hand, by arranging the weight-reducing portion 35 on the second surface F2, the spring seat 3 can be made lighter.

[0090] Furthermore, in the first end spring seat 3a, the axial dimension H2 of the second gap 82 is smaller than the axial dimension H1 of the first gap 81. Therefore, a larger hysteresis torque T can be generated compared to the case where the axial dimension H1 of the first gap 81 and the axial dimension H2 of the second gap 82 are the same, as in the first to third intermediate spring seats 3b, 3c, 3d and the second end spring seat 3e.

[0091] [Other embodiments] The present invention is not limited to the embodiments described above, and various modifications or alterations are possible without departing from the scope of the present invention.

[0092] (a) In the above embodiment, the weight-reducing portion 35 is positioned radially outward relative to the housing portion 36, but is not limited thereto. As shown in Figures 9A and 9B, the weight-reducing portion 35 may be positioned radially inward relative to the housing portion 36.

[0093] (b) In the above embodiment, the weight-reducing portion 35 is positioned radially outward relative to the housing portion 36, but is not limited thereto. As shown in Figures 10A and 10B, the weight-reducing portion 35 may have both a first weight-reducing portion 35a positioned radially outward relative to the housing portion 36 and a second weight-reducing portion 35b positioned radially inward relative to the housing portion 36.

[0094] In this modified example, the first weight-reducing portion 35a is larger than the second weight-reducing portion 35b. That is, the opening area of ​​the first weight-reducing portion 35a is larger than the opening area of ​​the second weight-reducing portion 35b. Also, in this modified example, the grease 4 is placed in the first weight-reducing portion 35a, but not in the second weight-reducing portion 35b.

[0095] (c) In the above embodiment, the weight-reducing portion 35 had a circular opening, but is not limited to this. As shown in Figures 11A and 11B, the weight-reducing portion 35 may have an opening that extends in the axial direction.

[0096] (d) In the above embodiment, the weight-reducing portions 35 were arranged in pairs on the radially inward and / or radially outward sides of the housing portion 36, but the invention is not limited thereto. As shown in Figures 11A and 11B, the weight-reducing portions 35 may be arranged with one on the radially inward side and one on the radially outward side of the housing portion 36.

[0097] (e) In the above embodiment, the first end spring seat 3a and the second end spring seat 3e had the same shape, and the first intermediate spring seat 3b, the second intermediate spring seat 3c, and the third intermediate spring seat 3d had the same shape, but the embodiment is not limited to this. For example, the first end spring seat 3a and the second end spring seat 3e may have different shapes, and the first intermediate spring seat 3b, the second intermediate spring seat 3c, and the third intermediate spring seat 3d may have different shapes.

[0098] (f) In the above embodiment, DMF100 was described as an example of a rotating device, but the rotating device is not limited to DMF100. For example, the rotating device does not have to be equipped with a secondary flywheel 5. The rotating device may also be a clutch device or a damper device, etc.

[0099] (g) In the above embodiment, the first end spring seat 3a was described as an example of the second rotating body, but the second rotating body may be any other spring seat 3. That is, it is sufficient that at least one of the multiple spring seats 3 has a weight-reducing portion 35. [Examples]

[0100] The following describes embodiments of the present invention. The following embodiments were obtained by numerical simulation analysis. However, the present invention is not limited to the embodiments described below.

[0101] [Preparation of DMF100] DMF100 was manufactured such that the representative radius R of the grease 4 in formula (1), the area A of the grease 4 in contact with the first end spring seat 3a, and the axial dimension H between the primary flywheel 2 and the first end spring seat 3a were as follows: In the first gap 81 and the second gap 82, the representative radius R was 115 mm, and the area A was 15.4 cm² (total of the first gap 81 and the second gap 82). 2 The dimensions H1: 0.5 mm and H2: 0.5 mm were used. The third gap 83 was omitted. The total hysteresis torque, which is the sum of the hysteresis torques T calculated for the first gap 81 and the second gap 82, was used as the hysteresis torque obtained for each test number.

[0102] In this simulation, the relative angular velocity ω during normal operation (not at engine startup, but during stable driving) was 50 deg / s. The relative angular velocity ω when resonance occurred at engine startup was 2000 deg / s. In other words, the relative angle when resonance occurred at engine startup was 40 times the relative angular velocity ω during normal operation.

[0103] Furthermore, in this simulation, the fluctuation range of the damper input torque during normal operation was ±20 Nm. When resonance occurred during engine startup, the fluctuation range of the damper input torque was ±100 Nm. In other words, the fluctuation range of the damper input torque when resonance occurred during engine startup was five times that of the damper input torque during normal operation.

[0104] As shown in Table 1, various greases with different viscosity indices n were prepared. The greases used in Test No. 1 and Test No. 2 are greases commonly used in conventional DMFs. Using the prepared greases, the increase ratio of the hysteresis torque at engine startup relative to the hysteresis torque during normal operation (hereinafter referred to as the hysteresis torque increase ratio) when the relative angular velocity between the primary flywheel 2 and the secondary flywheel 5 in the DMF100 is 40 times was simulated by numerical analysis using equation (1). The results are shown in Table 1 and Figure 12.

[0105] [Table 1]

[0106] [Evaluation Results] As described above, the fluctuation range of the damper input torque when resonance occurred during engine startup was five times that of the damper input torque during normal operation. Therefore, if the hysteresis torque increase rate is increased by five times or more, resonance occurring during engine startup can be sufficiently suppressed. As shown in Table 1 and Figure 12, the hysteresis torque increase rate was five times or more when the viscosity index n was 0.43 or higher. Thus, it was confirmed that resonance occurring during engine startup can be sufficiently suppressed if the viscosity index n is 0.4 or higher. [Explanation of Symbols]

[0107] 2. Primary flywheel (an example of a first rotating body) 3 Spring Seat 3a Spring seat for the first end (an example of a second rotating body) 4. Grease (an example of a viscous fluid) 21 Input section 21a Main body 21b Cylindrical part 35. Weight reduction section 40 Damper section 41 Coil springs 51 First output member 100 DMF (Example of a rotating device) O Rotation axis

Claims

1. The first rotating body and, A second rotating body is positioned with a gap between it and the first rotating body, and is rotatable relative to the first rotating body. A viscous fluid is disposed in the gap between the first rotating body and the second rotating body, Equipped with, The second rotating body has a first surface facing the first rotating body and a second surface not facing the first rotating body. The second rotating body has a weight-reducing portion on the second surface, The system further comprises an elastic member positioned adjacent to the second rotating body in the circumferential direction, The second rotating body has a housing portion for housing the elastic member on a surface facing the circumferential direction, The opening area of ​​the weight-reducing portion is smaller than the opening area of ​​the housing portion. The second rotating body has a circumferential surface facing the circumferential direction, The weight-reducing portion is arranged on the circumferential surface of the second rotating body, The weight-reducing portion is positioned radially outward or radially inward relative to the housing portion. The aforementioned weight-reducing portion is, A first weight-reducing portion is positioned radially outward from the aforementioned housing portion, A second weight-reducing portion is positioned radially inward from the aforementioned housing portion, It has, The first weight-reducing portion is larger than the second weight-reducing portion. Rotating device.

2. The aforementioned weight-reducing portion is a recess that opens in the circumferential direction. The rotating device according to claim 1.

3. The viscous fluid is distributed in the first cutout section but not in the second cutout section when the rotating device is in operation. The rotating device according to claim 1 or 2.

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