JPH10122265A - Power transmission device and frictional engagement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic clutch that is able to reduce any generating stress in a spring itself, whereas a low torsional spring constant is achieved, and also it makes durability against any deforming force in the torsional direction as well as to enable it to secure the sufficient displacement of an armature. SOLUTION: A spring 7 consists of a platelike first plate spring part 8 and a scrolllike second plate spring part 9. In this constitution, one end of the first plate spring part 8 is clamped tight to the front side end of an armature 5, one end of the second plate spring part 9 is connected to the other end of the first plate spring part 8, and the other end of the second plate spring part 9 is clamped tight to a mounting part 15 of an inner hub 6. In succession, the spring 7 like that is installed so as to superpose three pieces on each other at the front side end of the armature 5, and further the second plate spring part 9 is scrolledly installed over a range of 360 degrees. With this constitution, a part to be deformed in the torsional direction in this spring 7 is able to take longer so that a low torsional spring constant is thus securable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device applicable to a friction engagement device, a torque limiter, and the like, and is particularly suitable for an electromagnetic clutch or the like for intermittently rotating power from an engine to an engine accessory. It relates to an electromagnetic coupling device.

[0002]

2. Description of the Related Art Conventionally, an engine clutch such as a refrigerant compressor and a supercharger of an air conditioner for a vehicle has an electromagnetic clutch (magnet clutch) for interrupting transmission of rotational power from the engine to the engine accessory. It is installed. Generally, in this electromagnetic clutch, when the power supply to the electromagnetic coil is stopped, the armature on the engine accessory side is separated from the friction surface of the rotor on the engine side to return to the original position, so that the armature and A plurality of leaf springs are mounted between the armature and a connecting member that connects the engine accessory.

However, since the leaf spring is arranged so as to linearly connect the armature and the connecting member, the leaf spring is easily deformed in the axial direction of the armature, but is deformed in the torque transmitting direction (torsion direction). It was difficult to prevent torque fluctuations on the engine accessory side. So, the actual opening 63
Japanese Patent Application Laid-Open No.-78730 discloses that a leaf spring is formed in an arc shape so as to be disposed along a torsion direction, and a wavy bent portion is provided in the middle, so that the leaf spring is deformed in the torsion direction. An electromagnetic clutch provided with a leaf spring member adapted to absorb a force is also disclosed.

[0004]

However, in the conventional leaf spring member of the electromagnetic clutch, the bent portion is provided only in a part of the leaf spring having a limited length. In addition to obtaining a large amount of deformation, the generated stress is large because the leaf spring itself is short. In addition, since the axial spring constant for applying a restoring force of the armature when the power supply to the electromagnetic coil is stopped must be set to an appropriate value, the shape of the leaf spring is also very limited.

For this reason, torque fluctuation transmitted to the electromagnetic clutch increases in a frequency region near the torsional resonance point of the engine accessory, and when the resonance region is close to the resonance point of the vehicle, noise increases due to the synergistic effect. In the specifications of a leaf spring that obtains a low torsional spring constant enough to solve the torsional resonance problem of engine accessories, the amount of deformation in the torsional direction due to torque fluctuation increases, Due to the large amount of distortion, durability against the torsional deformation force could not be secured. In addition, there is a problem that a sufficient armature return force cannot be obtained when power supply to the electromagnetic coil is stopped.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the stress generated by a leaf spring itself while achieving a low torsional spring constant.
Another object of the present invention is to provide a power transmission device and a friction engagement device that can ensure durability against a deformation force in a torsional direction. Also,
An object of the present invention is to provide a power transmission device capable of obtaining a sufficient displacement of the second friction member and a friction engagement device.

[0007]

According to the first aspect of the present invention, a leaf spring member of a power transmission device is constituted by a leaf spring which is extended in a substantially arc shape so as to be along the rotation direction of the rotating member. Thereby, the portion of the leaf spring that is deformed in the torsional direction can be made longer.

As a result, even in a leaf spring specification for obtaining a low torsional spring constant enough to solve the torsional resonance problem,
The stress generated by the leaf spring in the torsional direction can be reduced, and the amount of distortion in the torsional direction of the leaf spring can be reduced, so that durability against the deformation force in the torsional direction can be ensured.

According to the second aspect of the present invention, the first friction member and the second friction member are frictionally engaged by connecting the second friction member to the first friction member by the driving means. Thereby, the rotational power of the driving source is transmitted to the second friction member connected to the movable member via the first friction member.
Alternatively, the rotation of the first friction member is stopped by the second friction member connected to the fixed member. At this time, friction is generated from the second leaf spring extending in a substantially arc shape along the rotation direction of the first friction member, the first leaf spring extending in a direction substantially perpendicular to the rotation direction of the first friction member, and the like. By configuring the leaf spring member of the engagement device, it is possible to increase the length of the portion of the second leaf spring that is deformed in the torsional direction.

As a result, even in the second leaf spring specification for obtaining a low torsional spring constant enough to solve the torsional resonance problem, the stress generated by the second leaf spring can be reduced by the length in the torsional direction. In addition, since the amount of distortion in the torsional direction of the second leaf spring is reduced, it is possible to ensure durability against the deformation force of the second leaf spring in the torsional direction. In addition, the second deformable in the torsional direction
By separately providing the leaf spring and the first leaf spring that is deformed in the axial direction, even if the displacement amount due to only the second leaf spring is insufficient, the displacement amount of the second friction member when operating the driving means is sufficient. Can be secured.

According to the third aspect of the present invention, when the electromagnetic coil is energized, a magnetic force is generated, so that the second friction member is connected to the first friction member against the reaction force of the first leaf spring. The first friction member and the second friction member are frictionally engaged with each other.
Further, when the energization of the electromagnetic coil is stopped, the magnetic force of the electromagnetic coil is lost, so that the second friction member is released from the first friction member by the reaction force of the first leaf spring. Only the first friction member is rotationally driven by the driving source.

According to the present invention, one end of the first leaf spring is connected to the second friction member, and the other end of the first leaf spring is connected to one end of the second leaf spring. Since the other end of the spring is connected to the connecting member, a second leaf spring having a low torsional spring constant can be achieved. Thereby, an effect similar to that of the second aspect is obtained.

According to the fifth aspect of the present invention, the number of parts of the leaf spring member is reduced by integrally forming the first plate spring having a flat plate shape and the second leaf spring having a spiral shape with one spring member. Since it can be reduced, the assembling workability is improved, so that the manufacturing cost of the leaf spring member can be reduced.

According to the sixth aspect of the present invention, the second leaf spring is disposed at an angle of 180 ° or more around the axis of the first friction member, thereby torsion of the second leaf spring. Since the length in the torsional direction can be lengthened, the stress generated in the second leaf spring can be extremely reduced, and the amount of distortion in the torsional direction of the second leaf spring is reduced. Durability against deformation force can be secured.

According to the present invention, by disposing a plurality of second leaf springs so as to overlap in a radial direction of the second friction member, a plurality of long deformations in the torsion direction are provided. The parts can be compactly assembled. Thus, the axial dimension and the radial dimension of the friction engagement device can be reduced, and the size of the friction engagement device can be reduced.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

1 to 7 show an embodiment in which a power transmission device and a friction engagement device according to the present invention are applied to an electromagnetic clutch of a compressor. FIGS. 1 and 2 show an entire electromagnetic clutch. FIG. 3 is a diagram showing a structure.

The electromagnetic clutch 1 is an electromagnetic coupling device which is mounted on a shaft of a compressor (not shown) of a refrigeration cycle and intermits rotational power from an engine (not shown) to the compressor as required. The compressor is used for an air conditioner for a vehicle (car air conditioner), and is an engine accessory that is rotationally driven by an engine.

The electromagnetic clutch 1 includes an electromagnetic coil 2, a stator housing 3 supporting the electromagnetic coil 2, a clutch rotor 4 to which the rotational power of the engine is transmitted, an armature 5 receiving the rotation of the clutch rotor 4, and an armature 5 And a hub assembly (which will be described later) that supports the above.

The electromagnetic coil 2 is a driving means according to the present invention, and is a well-known one in which a conductive wire provided with an insulating film is wound around a resin bobbin 11, and generates a magnetic force when energized. The electromagnetic coil 2 is molded and fixed to the outer periphery of the stator housing 3 using a nylon resin.
The stator housing 3 is made of a magnetic material such as iron, and is fixed to a housing (not shown) of the compressor via an annular plate 12.

The clutch rotor 4 is a first friction member of the present invention, and is made of a magnetic material such as iron, and is formed in a U-shaped cross section so as to cover the front of the electromagnetic coil 2 and the stator housing 3. Have been. This clutch rotor 4
A pulley 13 around which a multi-stage V-belt (not shown) is stretched is welded or the like to the outer peripheral surface of the pulley 13. Also,
A ball bearing (bearing) 14 mounted on the outer periphery of the compressor housing is press-fitted and fixed to the inner periphery of the clutch rotor 4. The front end surface of the clutch rotor 4 is a smooth friction surface for frictionally engaging with the armature 5.

The armature 5 is a second friction member and a rotating member according to the present invention, which is made of a magnetic material such as iron, is formed in an annular plate shape, and is provided with a clutch rotor through a predetermined gap in the axial direction. 4 are arranged to face the friction surface. This armature 5 has a smooth friction surface on the rear end surface facing the friction surface of the clutch rotor 4.

Next, a hub assembly according to the present embodiment will be described with reference to FIGS. Here, FIG. 3 and FIG. 4 are views showing a hub assembly to which one spring is mounted.

The hub assembly includes an inner hub 6 that rotates integrally with the compressor shaft, and three springs 7 that connect the armature 5 and the inner hub 6. The inner hub 6 is a connecting member of the present invention, and has an annular mounting portion 15 on the front side.
Has a stepped cylindrical fixed portion 16 extending rearward in the axial direction from the inner peripheral side of the fixed portion, and the inner periphery of the fixed portion 16 is fixed to the shaft of the compressor.

The three springs 7 are made of, for example, a spring member such as stainless steel or spring steel, and have a flat first leaf spring portion 8 fixed to the front end face of the armature 5 and a first leaf spring portion. Each of the second leaf springs 9 has a spiral shape extending from an end of the second leaf spring 8.

The first leaf spring portion 8 is the first leaf spring of the present invention, and has one end (for example, the tip in the rotational direction) fixed to the outer peripheral side of the front end face of the armature 5 with a rivet 17. The first plate spring portion 8 is a flat plate portion of the spring 7 having a plate thickness of 2.4 mm and arranged to spread in an arc shape in a direction parallel to the surface direction of the front end face of the armature 5. It is an axial elastic deformation portion that is displaced in the axial direction (axial direction of the shaft). And the first leaf spring portion 8
When the armature 5 is attracted to the friction surface of the clutch rotor 4, the armature 5 is elastically deformed in the axial direction, and is restored to the initial state so as to return the armature 5 to the original position when the power supply to the electromagnetic coil 2 is stopped.

The second leaf spring portion 9 is the second leaf spring of the present invention, and has one end (for example, the tip in the rotational direction) integrally connected to the other end of the first leaf spring portion 8 and the other end ( For example, the rear end in the rotation direction) is fixed to the outer peripheral side of the front end surface of the mounting portion 15 of the inner hub 6 with a rivet 18. The second plate spring portion 9 has a plate thickness of 2.4 mm, and a plate-like portion that stands upright in a direction (axial direction) substantially perpendicular to the surface direction of the armature 5 from the outer peripheral end (one end) to the inner peripheral end. A spiral portion of the spring 7 that is spirally disposed so that the inner diameter gradually decreases toward the other end, and is elastic in a torsional direction that is displaced in the torsional direction of the armature 5 (the rotational direction of the shaft). It is a deformed part. The second leaf spring portion 9 buffers sudden torque from being applied to the shaft of the compressor when the armature 5 is attracted to the friction surface of the clutch rotor 4 and reduces torque fluctuation of the shaft of the compressor.

As shown in the graph of FIG. 5 showing the relationship between the torsion spring constant and the spring length, the second leaf spring portion 9 has a simple arc-shaped conventional technique (spring length 50 mm). Since the spring length can be set to 250 mm by making the spiral shape as compared with, a torsional spring constant (about 30 Nm / rad: about 1/1 of an existing rubber hub) that can solve the torsional resonance problem.
0). Further, the second leaf spring portion 9 is provided around the axis of the clutch rotor 4 and the armature 5.
It is arranged spirally over 60 °. And 3
The individual springs 7 increase the length of the second leaf spring portion 9,
In order to assemble the armature 5 compactly on the front side, the armature 5 is spirally disposed so as to overlap in the radial direction orthogonal to the axial direction of the armature 5.

[Operation of Embodiment] Next, the operation of the electromagnetic clutch 1 of this embodiment will be briefly described with reference to FIGS.

The armature 5 is attracted to the clutch rotor 4 side against the reaction force (elastic force) of the first leaf spring portion 8 of the three springs 7 by the magnetic force generated by energizing the electromagnetic coil 2. As a result, the friction surface of the clutch rotor 4 and the friction surface of the armature 5 are attracted (closely contact) and frictionally engaged, so that the rotational power of the engine transmitted to the clutch rotor 4 via the pulley 13 is transmitted to the armature 5, The power is transmitted to the compressor shaft via three springs 7 and the inner hub 6. Thus, the interior of the vehicle is air-conditioned by the compressor sucking, compressing, and discharging the refrigerant.

At this time, when the load torque of the compressor shaft fluctuates due to the compression action of the refrigerant (torque fluctuation occurs), the torque fluctuation includes the spiral second leaf spring portion 9 from the shaft via the inner hub 6. It is transmitted to three springs 7. Here, according to the graph of FIG. 5, the torsional spring constant is 22 because the spring length is 50 mm in the prior art.
In this embodiment, the spring length was 250 mm, but the torsional spring constant was 33 (Nm / rad).
rad). For this reason, the second leaf spring portion 9 has a low torsional spring constant, and the resonance point of the torque fluctuation becomes smaller than the resonance frequency of the vehicle, whereby the resonance between the clutch rotor 4 and the inner hub 6 can be prevented. As a result, vibration due to resonance is not transmitted to the engine and the vehicle body, so that noise in the vehicle interior can be reduced.

When the energization of the electromagnetic coil 2 is stopped, the generated magnetic force disappears (demagnetizes). Therefore, the armature 5 that has been attracted to the clutch rotor 4 side has the first spring 3 of the three springs 7. The plate spring 8 is separated from the clutch rotor 4 by the reaction force (restoring force) and returns to the original position. As a result,
The rotational power of the engine transmitted to the clutch rotor 4 is not transmitted to the shaft of the compressor, and
Only idles.

[Effects of the Embodiment] As described above, the electromagnetic clutch 1 is configured such that the second leaf spring portion 9 of the spring 7 is arranged in a spiral shape of 360 °, thereby deforming in the torsion direction. By increasing the spring length of the leaf spring portion 9, a low torsional spring constant enough to solve the torsional resonance problem can be obtained. As a result, the generated stress of the spring 7 can be reduced by an amount corresponding to the length of the spring 7 in the torsional direction, and the amount of distortion of the spring 7 in the torsional direction is reduced. Durability can be secured.

Then, the first leaf spring portion 8 deformed in the axial direction
And the second leaf spring portion 9 which is deformed in the torsion direction can be provided separately, so that the displacement of the armature 5 when the electromagnetic coil 2 is energized can be sufficiently secured, so that malfunction of the electromagnetic clutch 1 can be prevented. Can be. The axial spring constant is a flat plate-shaped first spring independent of the spiral second plate spring 9.
Since it can be set by the leaf spring portion 8, the first and second leaf spring portions 8,
Even if 9 is an integral structure, it is possible to easily perform a design that simultaneously satisfies the required spring characteristics in the torsion direction and the axial direction.

The number of parts of the spring 7 can be reduced by integrally forming the plate-like first leaf spring portion 8 and the spiral second leaf spring portion 9 with one spring member.
The assembly workability is improved. As a result, the manufacturing cost of the spring 7 can be reduced, so that the price of the electromagnetic clutch 1 can be reduced. By disposing the second leaf spring portions 9 of the three springs 7 so as to overlap in the radial direction of the armature 5, the second leaf spring portions 9 can be compactly assembled. Thereby, the axial dimension and the radial dimension of the electromagnetic clutch 1 can be reduced, so that the electromagnetic clutch 1 can be downsized.

[Experimental Results of the Embodiment] First, the second
An experiment in which the spring length of the leaf spring portion 9 is variously changed to investigate how the torsional spring constant changes will be described. In this experiment, the spring length of the second leaf spring portion 9 of the spring 7 was changed, and the torsional spring constant was investigated. The experimental results are shown in the graph of FIG. It can be seen from the graph of FIG. 5 that the longer the spring length of the spring 7, the lower the torsional spring constant.

Here, the conventional technique is disclosed in Japanese Utility Model Laid-Open No. 63-787.
No. 30 discloses an electromagnetic clutch having a leaf spring.
The conventional leaf spring has a plate thickness of 1 mm and a radius of 5 mm.
mm is provided at three places with a wavy shape. In the case of this leaf spring, the torsional spring constant is 2200 Nm / ra.
d, which is higher than that of the rubber hub of the related art as described later. When a rubber hub is provided between the outer hub and the inner hub as the hub member, the torsional spring constant is about 400 Nm / rad. As shown in the graph of FIG. 5, the torsion spring constant of the spring 7 of this embodiment is 33 Nm / rad in a calculated value when the plate thickness is 2.5 mm and the spring length is 250 mm. Value 30Nm
/ Rad to 40 Nm / rad.

Next, a description will be given of an experiment for examining how the amplitude torque changes by variously changing the rotation speed of the compressor. In this experiment, the rotational speed of the compressor was changed, and the amplitude torque of the one employing this embodiment and the amplitude torque of the one employing the conventional technique were investigated. The experimental results are shown in the graphs of FIGS. It was shown to. Here, the present embodiment is an electromagnetic clutch 1 having a spring 7 having a plate thickness of 2.5 mm and a spring length of 250 mm. The conventional technology is an electromagnetic clutch in which a rubber hub is provided between an outer hub and an inner hub as a hub member. is there. In the graph of FIG. 6 and the graph of FIG. 7, OA is the overall value of the amplitude torque, and 10th is the value of the 10th-order component of the amplitude torque.

As can be seen from the graph of FIG. 7, the resonance rotational speed of the prior art was 1050 rpm,
As can be seen from the graph of FIG. 6, the resonance rotation speed of the present embodiment is 500 times lower than the normal idle rotation speed.
rpm. Therefore, since the resonance rotational speed of the present embodiment is lower than the resonance frequency of the vehicle, it can be seen that resonance between the clutch rotor 4 and the inner hub 6 can be prevented.

[Modification] In this embodiment, the first flat plate spring portion 8 and the second flat spring portion 9 are formed integrally with each other. The second leaf spring portion 9 may have a separate structure. Further, even if the first flat plate spring portion 8 is not provided, the first second plate spring portion 8 is deformed in both the axial direction and the torsion direction only by the spiral second plate spring portion 9, so that the first flat spring portion 8 is eliminated. You can also.

In this embodiment, the present invention is applied to the electromagnetic clutch 1 for intermittently rotating the power from the engine to the shaft of the compressor. However, the supercharger (supercharger), the blower, the fluid pressure pump, the transmission The present invention may be applied to an electromagnetic clutch that interrupts the rotational power to an engine accessory such as the one described above. Further, the present invention may be applied to another electromagnetic coupling device such as an electromagnetic brake instead of the electromagnetic clutch.

In the present embodiment, the electromagnetic coil 2 is used as a driving means for sucking (driving) the armature 5 so that the armature 5 is attracted to the clutch rotor 4.
A fluid pressure such as a hydraulic pressure may be used as a driving unit for driving the friction member. That is, the present invention may be applied to other friction engagement devices such as a hydraulic type multi-plate clutch and a hydraulic type multi-plate brake. Further, the present invention may be applied to other power transmission devices such as a torque limiter and a damper device.

In this embodiment, the hub assembly is constituted by three springs 7, but the hub assembly may be constituted by one or more springs 7. However, when the hub assembly is constituted by one spring 7, stable support of the armature 5 is difficult. Further, the second leaf spring portion 9 is set at 360 °
The second leaf spring portion 9 is
It may be arranged spirally over 0 ° or more. In addition, 1
Even when the angle is 80 ° or more, the torsional spring constant can be reduced. However, the larger the value is, the lower the torsional spring constant can be.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing an electromagnetic clutch (embodiment).

FIG. 2 is a front view showing an electromagnetic clutch (Example).

FIG. 3 is a front view showing a hub assembly to which one spring is mounted (Example).

FIG. 4 is a half sectional view showing a hub assembly to which one spring is mounted (Example).

FIG. 5 is a graph showing a relationship between a torsion spring constant and a spring length (Example).

FIG. 6 is a graph showing a relationship between an amplitude torque and a rotation speed of a compressor (Example).

FIG. 7 is a graph showing a relationship between an amplitude torque and a rotation speed of a compressor (prior art).

[Explanation of symbols]

 Reference Signs List 1 electromagnetic clutch (power transmission device, friction engagement device) 2 electromagnetic coil (drive means) 4 clutch rotor (first friction member) 5 armature (second friction member, rotating member) 6 inner hub (connection member) 7 spring (plate) Spring member) 8 Flat first leaf spring portion (first leaf spring) 9 Spiral second leaf spring portion (second leaf spring)

Claims (7)

[Claims] A rotating member to which rotational power is transmitted from a driving source; a connecting member connected to a movable member or a fixed member;
A power transmission device comprising: a leaf spring member that connects the rotating member and the connecting member and deforms in a torsional direction, wherein the leaf spring member extends along a rotation direction of the rotating member. A power transmission device comprising a spiral leaf spring which is extended in a substantially arc shape and has an inner diameter gradually reduced from one end to the other end. 2. A first friction member to which rotational power of a drive source is transmitted, a second friction member arranged to face the first friction member and engaged with the first friction member when connected, Driving means for connecting the second friction member to the first friction member, a connection member connected to a movable member or a fixed member,
While connecting the second friction member and the connection member,
A friction engagement device comprising: a leaf spring member that deforms in a torsion direction and an axial direction, wherein the leaf spring member extends in a direction substantially orthogonal to a rotation direction of the first friction member. A first leaf spring, and a spiral second leaf spring extending in a substantially arc shape along the rotation direction of the first friction member and having an inner diameter gradually reduced from one end to the other end. A friction engagement device, characterized by: 3. The frictional engagement device according to claim 2, wherein the drive means generates a magnetic force when energized, thereby causing the first frictional member to attract the second frictional member and frictionally engage the first frictional member. A frictional engagement device, wherein the frictional engagement device is an electromagnetic coil. 4. The friction engagement device according to claim 3, wherein the first leaf spring has one end connected to the second friction member, and the second leaf spring has one end connected to the first leaf spring. The friction engagement device is connected to the other end, and the other end is connected to the connection member. 5. The friction engagement device according to claim 2, wherein the first leaf spring and the second leaf spring are integrally formed by one spring member. A friction engagement device characterized by the above-mentioned. 6. The friction engagement device according to claim 2, wherein the second leaf spring extends over 180 ° about the axis of the first friction member. A friction engagement device, which is provided. 7. A friction engagement device according to claim 2, wherein a plurality of said second leaf springs are arranged in parallel, and said plurality of second leaf springs are arranged in parallel. , Wherein the second friction member overlaps in the radial direction.