JPH034837Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to an improvement of a multi-gap powder clutch used in a power transmission path of a vehicle.

[Prior Art] Powder clutches that use powder (magnetic iron powder) as a torque transmission medium have the following advantages: the transmission torque is approximately proportional to the excitation current, so precise torque control can be easily performed; It is widely known as a clutch used in automobiles and the like because it has excellent properties such as being almost unaffected by slip speed. A conventional powder clutch with improved characteristics is disclosed in Japanese Patent Publication No. 37-8853, for example.
This is an attempt to improve various performances of a single-gap powder clutch by forming the powder gap in an inclined shape so that the central part in the axial direction is narrower than the opposite ends. The principle of this technology is as follows. That is, although it differs somewhat depending on the magnetic path shape, Fig. 7A
As shown in , the magnetic flux density tends to be dense at both ends A and B of the powder gap, and sparse at the center C. Therefore, if powder leaks out of the gap, the powder will concentrate at both ends A and B of the gap, creating a so-called powder barrier. When this happens, external powder is prevented from entering the inside, and the powder density of the powder gap as a whole becomes sparse, which not only reduces power transmission performance, but also
Since a large amount of power is transmitted only through these end portions, heat is generated in the slip condition and the product seizes up, causing powder deterioration. However, as shown in FIG. 7B, if the powder gap is formed so that the axial center part C is inclined so that it is narrower than both ends A and B, the magnetic flux density at the center part C becomes high. As a result, the powder is attracted to the central portion C, and the powder barrier as described above is not formed, and the powder can quickly enter the gap.

[Problem that the invention attempts to solve]

However, the reality is that this technology has not been widely used and has remained hidden. This is due to the following reason. That is, the size of the powder gap is generally about 0.4 to 1.2 mm, and the most commonly used size is 0.8 mm. Furthermore, the air gap (see FIG. 8A) created when the powder sticks to the outer circumferential friction surface due to centrifugal force is generally about 0.03 to 0.15 mm. As a result, at this level of gap size,
For example, 0.6 so that the magnetic flux distribution is closer to the center.
If you try to create an inclination of ~1.0mm, Figure B
As shown in FIG. 2, the powder is constantly being dragged in the center portion C, resulting in a problem that the dragging torque increases.

[Purpose of invention]

The present invention was developed in view of the above-mentioned conventional problems, and employs the above-mentioned inclination technology in an optimal configuration for a multi-gap powder clutch, improving the disengagement performance of the entire powder clutch (reducing drag torque), and improving control response. It is an object of the present invention to provide a multi-gap powder clutch which can improve performance and stability of transmission force, and can also prevent shortening of life due to powder scattering and powder burnout. .

[Means to solve the problem]

The present invention provides two powder gaps in which powder is inserted between a driving side member and a driven side part so that a magnetic path can be formed coaxially and through the powder, and both powder gaps are arranged in the axial direction. The powder gap is formed in an inclined shape so that the central part thereof is narrower than both ends thereof, and the inclination angle of the two powder gaps is such that the powder gap with the driving side member located on the inner circumferential side is larger than the driven side member. The above object has been achieved by setting the powder gap to have a larger angle than that of the powder gap located on the inner circumferential side. Further, in an embodiment of the present invention, the air gap generated in the two powder gaps is 0.1 to 0.15.
mm, the inclination angle set to the larger angle is set to less than tan ^-1 (0.3/2L), where L is the actual distance in the axial direction of the powder gap from the center, and various characteristics are determined. This is intended to achieve a good balance between improvement and reduction of dragging torque. Further, in another embodiment of the present invention, grooves are formed in the circumferential direction on the opposing surfaces sandwiching the two powder gaps, thereby further improving the characteristics of the clutch as a whole. be.

[Effect]

In the present invention, we focused on a multi-gap powder clutch equipped with two powder gaps, and the inclination angle of the taper was shared between the two powder gaps, so the inclination angle per piece could be set small. It is possible to reduce the drag torque by the same amount. Also, at this time, the powder gap where the driving side member is located on the inner circumferential side is set at a larger angle than the powder gap where the driven side member is located on the inner circumferential side, so the powder is agitated and the characteristics deteriorate. It is possible to actively improve the properties of the powder gap, which tends to occur, and thus maintain the properties of the powder clutch as a whole.

【Example】

Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIGS. 1 and 2 show an embodiment of a double gap type powder clutch according to the present invention. In the figure, 10 is a first driving side member, 20 is a second driving side member, 30 is a driven side member, and S ₁ and S ₂ are the first and second powder gaps, respectively. The first driving member 10 is disposed on the outer periphery of the driven member 30 with a predetermined powder gap _S1 . The first drive side member 10 includes a support member 12, a member 14 facing the driven side member 30, and a cover labyrinth member 16. The facing member 14 facing the driven member 30 is made of a magnetic material such as S10, and the support member 12 is made of a non-magnetic material such as Al. Further, the cover labyrinth member 16 is also made of Al or the like, and is fastened with bolts. The second drive side member 20 is made of a magnetic material, such as S10, and is disposed at the inner circumferential position of the driven side member 30 with a predetermined powder gap _S2 . The first drive side member 10 and the second drive side member 20 are connected via a connection member 70 arranged on the right side in the figure. This connecting member 70 is made of a non-magnetic material, for example SUS304.
The connecting member 70 and the first drive side member 10 are connected by bolts 7
2, and the connecting member 70 and the second drive side member 20 are integrally connected by bolts 74 (see FIG. 1). Both drive side members 10, 20 are connected to an input shaft (not shown) via a flange 52. Also, both drive side members 1
0 and 20 are positioned with respect to the driven member 30 via a connecting member (made of SUS304 material) 71 by bearings 60 and 62, and are rotatably supported. The driven side member 30 has an excitation coil 3 inside.
4, and the area around the excitation coil 34 is a magnetic field forming section 36. This magnetic field forming section 36
is made of magnetic material S10 or the like. The driven member 30 is connected to the hub 40 which is the output member.
They are connected by bolts via a damper mechanism 90 shown in the figure. A slip ring 46 is provided on the left side of the damper mechanism 90 in the figure. This slip ring 46 is for supplying power to the excitation coil 34 through a wiring 48. The first and second powder gaps S ₁ and S ₂ are
It is formed coaxially between the driving side member 10 and the driven side member 30, and between the second driving side member 20 and the driven side member 30. Powder is inserted into both powder gaps S ₁ and S ₂ , and the magnetic path S is inserted through this powder.
is said to be possible. Both powder gap S ₁ ,
S ₂ is formed in a tapered shape such that the central portion in the axial direction is narrower than both ends. Also, the inclination angles of both powder gaps θ ₁ , θ ₂
The inclination angle θ ₂ of the second powder gap S ₂ in which the driving side member is located on the inner periphery side is larger than the inclination angle θ ₁ of the first powder gap S ₁ in which the driven side member is located on the inner periphery side. It is set to be. Each of the powder gaps S ₁ and S ₂ is set so that an air gap of 0.1 to 0.15 mm is generated in the non-driving state. Furthermore, the inclination angle θ ₂ of the larger angle is set to be equal to or less than tan ⁻¹ (0.3/2L), where L is the actual distance in the axial direction from the center. Further, grooves 28 and 38 are formed in the circumferential direction on the opposing surfaces sandwiching the powder gaps S ₁ and S ₂ . Next, the operation of this embodiment will be explained. First, the connecting action of this double-gap powder clutch is performed by energizing the excitation coil 34 through the slip ring 46 and the wiring 48. When the excitation coil 34 is energized, a magnetic path S as shown by the broken line in FIG. 2 is generated. That is, a magnetic flux is generated that circulates between the magnetic field forming member 36 of the driven member 30, the member 14 of the first driving member 10 facing the driven member 30, and the second driving member 20. Note that the direction of this magnetic flux is determined by the direction of the excitation coil 34.
The direction can be reversed by reversing the winding of the coil or reversing the direction of the excitation current. Due to the generation of such magnetic flux, the powders arranged in the first and second powder gaps S ₁ and S ₂ are connected to each other in a chain shape, and due to the frictional force and electromagnetic coupling force between the powders, The first drive side member 10, the second drive side member 20, and the driven side member 30 are coupled, and power is transmitted from an input shaft (not shown) to the output hub 40. The powder clutch release action is performed by the excitation coil 3.
This is done by deactivating 4. That is, by deenergizing the excitation coil 34, the magnetic flux disappears and the powder is uncoupled, so that no power is transmitted. In the above case, in this example,
By focusing on a multi-gap powder clutch, the inclination angle of the taper is shared between two powder clutches, which allows the inclination angle of each clutch to be set small, thereby reducing drag torque accordingly. can be achieved. In addition, when setting the angle, the angle θ ₂ of the second powder gap S ₂ where the drive side member is located on the inner peripheral side
is set to a larger angle than the angle θ ₁ of the first powder gap S ₁ where the driven member is located on the inner circumferential side, the powder is agitated and the characteristics of the gap, which tends to deteriorate, are actively improved. Therefore, the characteristics of the powder clutch as a whole can be maintained well. That is, to explain this principle using FIGS. 3 and 4, first, as schematically shown in FIG. 3A, when the driven member d is located on the inner peripheral side, the coil is in a non-excited state In this case, the movement of the powder depends only on the centrifugal force of the driving member D. In this state, the powder sticks to the friction surface on the driving side member D side due to centrifugal force, and as a result, an air gap a is formed, the clutch is in a completely disengaged state, and the drag torque is small. Powder is also politely rejected.
When the coil is energized from this state and enters the operation transmission state, as shown in Figure B, the powder is held in an orderly manner, so power is immediately transmitted well. On the other hand, as shown in FIG. 4A, when the drive side member D is located on the inner peripheral side, the powder is stirred by the drive side member D, scattered, and stored in a disordered state. . Therefore, even in the non-excited state, a small amount of power is transmitted due to the collision between the powders, resulting in a large drag torque. Also, when the magnet is energized from this state, the powder in the gap may be scattered or poorly stored, so the density of the powder in the gap decreases, resulting in a decrease in power transmission performance and instability. becomes. Furthermore, since it takes a long time for the powder to move into the gap, the control responsiveness when changing the power transmission performance by the excitation current of the clutch decreases. Furthermore, the powder outside the powder gap concentrates on both ends A and B of the gap due to the magnetic flux generated by the coil excitation, forming a so-called powder barrier, which causes uneven burns on the friction surface, seizure, and oxidation, deterioration, and wear of the powder. becomes. In this example, in view of these circumstances,
Since the inclination angle θ ₂ of the taper of the second powder gap S ₂ where the deterioration of the characteristics is more significant, that is, the drive side member is located on the inner circumferential side, is made larger, the performance of the entire clutch can be significantly improved. , its inclination angle θ ₂
By setting the maximum value of Tan ^-1 (0.3/2L) or less, it is possible to maintain low drag torque while improving characteristics through taper formation. Also, in this embodiment, both powder gaps
Since grooves 28 and 38 are formed in the circumferential direction on the opposing surfaces that sandwich S ₁ and S ₂ , the air gap, which tends to become smaller due to taper formation, can be made larger than one without grooves. , and the drag torque can be reduced accordingly. That is, to explain this principle using Figs. 5 and 6, first, as shown in Figs. 5A and 6, the powder in the Z part of the figure moves as the clutch is turned on and off. Since the clutch is connected, the air gap when not energized is generally determined by the ratio of X:Y. Therefore, Fig. 6 A, B
By grooving, as shown in
X'=ΣX ₀ <X, and while ensuring a large air gap, the moving distance of each powder can be reduced, reducing drag torque and improving responsiveness.

[Effect of the idea]

As explained above, according to the present invention, it is possible to improve the power transmission performance in the powder gap of the clutch, especially in the powder gap whose inner circumferential side is the driving side member, to prevent the reduction in life due to powder scattering and powder burnout, and to prevent reduction in the lifespan due to powder scattering and powder burnout. This provides excellent effects such as improving control responsiveness by shortening the powder gathering time and preventing an increase in drag torque due to powder agitation.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of a multi-gap powder clutch according to the present invention, FIG. 2 is a partially enlarged cross-sectional view of the above-mentioned embodiment, and FIGS. 3A, B to 6A, B.
7A and 8B are partial vertical cross-sectional views schematically showing a single-gap powder clutch for explaining the operation of the above-mentioned embodiment, respectively. FIG. 3 is a partial vertical sectional view schematically showing a powder clutch. DESCRIPTION OF SYMBOLS 10...First drive side member, 20...Second drive side member, 30...Driver side member, 28, 38...Groove portion, _S1 ...First powder gap, _S2 ...Second powder gap, L... ... Actual axial distance from the center, A, B... Both ends of the gap, C... Center of the gap. θ ₁ , θ ₂ ...Inclination angle.

Claims (1)

[Claims for Utility Model Registration] (1) Two powder gaps in which powder is inserted are provided coaxially between the driving side member and the driven side member so that a magnetic path can be formed through the powder, and Both powder gaps are formed in an inclined shape so that the center portion in the axial direction is narrower than both end portions, and the inclination angle of the two powder gaps is set such that the drive side member is located on the inner peripheral side. A double-gap powder clutch characterized in that the driven side member is set at a larger angle than the powder gap located on the inner peripheral side. (2) When the air gap generated in the two powder gaps is 0.1 to 0.15 mm, the inclination angle of the larger angle is tan ^-1 , where L is the actual axial distance of the powder gap from the center. (0.3/2L) The first claim for registration of a utility model characterized by being set below (0.3/2L)
The multi-gap powder clutch described in Section 1. (3) A utility model according to claim 1 or 2, characterized in that a groove is formed in the circumferential direction on the opposing surfaces with the two powder gaps interposed therebetween. Multi-gap powder clutch.