JP2004239405A - Clutch device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize the simplification of a constitution of a clutch device 1, which switches a connection state to transmit rotational power between a first rotating shaft 2 and a second rotating shaft 3 to be arranged along on the same axis line and a disconnection state not to transmit it, and the cost reduction. <P>SOLUTION: Centrifugal friction members 10, 11, which are operated corresponding to the magnitude of centrifugal force, are made to automatically execute the operation of whether rotational resistance is imparted to a clutch body 5 or not in order to switch the connection state and the disconnection state. By this, the constitution can be made simpler compared with the conventional electromagnetic brake, and at the same time, a device and power for controlling operations of the electromagnetic brake are not required. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a clutch device.
[0002]
[Prior art]
The present applicant has proposed a clutch device having a simple configuration (see Patent Document 1). The clutch device includes a cylindrical shaft, a central shaft inserted into the inner periphery of the cylindrical shaft so as to be relatively rotatable via a rolling bearing, and a central shaft that is inserted into the inner periphery of the cylindrical shaft so as to face the same axis as the central shaft. A control shaft to be disposed, and a cutting state in which no rotational power is transmitted between the cylindrical shaft and the central shaft when the control shaft does not receive rotational resistance; And a clutch operating portion for establishing a connection state for transmitting rotational power between the shaft and the central shaft. Note that an electromagnetic brake is used to impart rotational resistance to the control shaft.
[0003]
[Patent Document 1]
JP-A-2002-213500
[Problems to be solved by the invention]
In the process of developing the clutch device, the applicant of the present application has found that the structure is further simplified and the cost is reduced.
[0005]
[Means for Solving the Problems]
The clutch device according to the present invention switches between a connected state in which rotational power is transmitted between the first and second rotary shafts disposed along the same axis and a disconnected state in which the rotational power is not transmitted. A clutch body fitted with a friction surface so as to be relatively displaceable in the axial direction and the circumferential direction, a friction surface provided on the second rotating shaft, the friction surface of the clutch body being in contact with and separated from the clutch body; An urging member that constantly urges the friction surface of the body in a direction away from the friction surface on the second rotation shaft side; and a device that imparts rotational resistance to the clutch body when not receiving a predetermined centrifugal force or more. A centrifugal friction member that does not impart rotational resistance to the clutch body when subjected to a predetermined centrifugal force, and a clutch element that applies rotational resistance to the clutch body with the centrifugal friction member. The friction surface While the frictional surface of the rotating shaft is pressed against the friction surface to establish the connection state, when the centrifugal friction member does not impart rotational resistance to the clutch body, the friction surface of the clutch body is moved to the second rotating shaft. And a cam mechanism that separates from the friction surface to set the cutting state.
[0006]
In this configuration, whether or not rotational resistance is applied to the clutch body is automatically determined by a centrifugal friction member that operates with centrifugal force. Thus, unlike the conventional electromagnetic brake, the configuration can be simplified, and a device and electric power for controlling the operation of the electromagnetic brake are not required.
[0007]
The cam mechanism includes a fixed ring that is axially and circumferentially immovably fitted to the outer periphery of the first rotation shaft on the outer end side of the clutch body and adjacent to the clutch body in the axial direction. A cam groove which is provided at several places on the surface of the clutch body facing each other and whose groove depth is set to be gradually shallower at least in one circumferential direction; A clutch ball to be mounted, and when the clutch ball is located in a deep portion of the two cam grooves, while bringing the clutch body closer to the fixed ring side to separate the two friction surfaces, When the clutch ball is located at a shallow portion of the two cam grooves, the clutch body may be moved away from the fixed ring body so that the friction surfaces are pressed against each other.
[0008]
In this case, the connected state and the disconnected state are easily maintained, and the operation is stabilized.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
1 to 7 show an embodiment of the present invention. The clutch device 1 shown in the figure has a clutch connection state for transmitting rotational power between a first rotary shaft 2 and a second rotary shaft 3 disposed along the same axis, and a clutch for interrupting the transmission of rotational power. It switches to the disconnected state.
[0010]
The axially intermediate region on the outer peripheral surface of the first rotating shaft 2 is set to have a large diameter. The second rotating shaft 3 has a shaft portion 3a having spline teeth 3c formed on the outer periphery, and a cylindrical portion 3b integrally formed at the shaft portion 3a at the end on the first rotating shaft 2 side.
[0011]
The inner end side of the first rotating shaft 2 is inserted into the inner periphery of the cylindrical portion 3b of the second rotating shaft 3 via a rolling bearing 20 such as a deep groove ball bearing so as to be relatively rotatable. A rolling bearing 21 such as a deep groove ball bearing is mounted on the outer end side of the first rotating shaft 2.
[0012]
The fixed ring 4 and the clutch body 5 are fitted in the large-diameter region of the first rotating shaft 2 so as to be adjacent to each other in the axial direction. Specifically, the cylindrical portion 4a of the fixed ring body 4 is "clear-fit" to the first rotating shaft 2, and the cylindrical portion 5a of the clutch body 5 is axially and circumferentially fitted to the first rotating shaft 2. "Gap fit" so as to be relatively displaceable. These two annular bodies 4 and 5 are positioned in the axial direction by rolling bearings 20 and 21 attached to both axial ends of the first rotary shaft 2. A disc spring 7 is interposed between the clutch body 5 and the rolling bearing 20 on the right side in the figure as an urging member for urging the clutch body 5 toward the fixed ring body 4.
[0013]
A pair of cam grooves 4c and 5c are provided at several locations on the circumference of each of the facing surfaces of the flanges 4b and 5b of the fixed ring 4 and the clutch body 5. A ball for clutch 6 is interposed between the cam grooves 4c and 5c. Each of the cam grooves 4c and 5c is formed in a long groove shape along the circumferential direction, and has a mortar shape that gradually becomes shallower from the center in the circumferential direction toward both sides in the circumferential direction.
[0014]
The cam groove 4c of the fixed ring 4, the cam groove 5c of the clutch body 5, and the clutch ball 6 constitute a cam mechanism. That is, this cam mechanism causes the clutch ball 6 to roll in the circumferential direction between the two cam grooves 4c and 5c with the relative rotation of the fixed ring body 4 and the clutch body 5 to move the movable member 5 relative to the control member 4. Operate to move closer and further away.
[0015]
On the inner peripheral surface on the opening side of the cylindrical portion 3b of the second rotating shaft 3, there is provided a tapered cone-shaped friction surface 3d whose diameter increases outward. The outer peripheral surface of the clutch body 5 is a tapered cone-shaped friction surface 5d that matches the friction surface 3d provided on the cylindrical portion 3b of the second rotating shaft 3.
[0016]
A gear 22 is attached to an outer diameter portion of the flange portion 4b of the fixed ring body 4 by a bolt. An output gear such as a motor (not shown) is meshed with the gear 22. On the other hand, a gear 23 is spline-fitted to the spline teeth 3c of the shaft portion 3a of the second rotating shaft 3. The gear 23 is positioned in the axial direction by a rolling bearing 24 such as a deep groove ball bearing and the like, which is provided on the right side in the figure at the shaft portion 3a and the cylindrical portion 3b.
[0017]
In the space between the inner periphery of the cylindrical portion 3b of the second rotating shaft 3 and the outer periphery of the cylindrical portion 5a of the clutch body 5, two semi-cylindrical brake shoes 10, 11 as centrifugal friction members are cylindrical. It is arranged to become. One end of each of the brake shoes 10 and 11 is swingably supported on the inner bottom of the cylindrical portion 3b of the second rotating shaft 3 via pins 12a and 12b. 13 are mounted so as to be close to each other. In addition, convex portions 10 a and 11 a that are in contact with the outer peripheral surface of the cylindrical portion 5 a of the clutch body 5 are provided on the inner diameter portions of the brake shoes 10 and 11. The projections 10a and 11a are provided near the pins 12a and 12b in the brake shoes 10 and 11, and by this arrangement, a large frictional force can be applied to the outer peripheral surface of the cylindrical portion 5a.
[0018]
Next, the operation will be described. Here, the rotational power of a motor (not shown) is input to the first rotating shaft 2 via the gear 22, and the first rotating shaft 2 is moved from the first rotating shaft 2 to the second rotating shaft 3 in accordance with the rotating speed of the first rotating shaft 2. It transmits or shuts off the rotational power. That is, the first rotating shaft 2 is set to the input side of the rotating power, and the second rotating shaft 3 is set to the output side.
[0019]
First, when the first rotating shaft 2 is not rotating, as shown in FIG. 6, the clutch balls 6 are located at the shallow portions of the two cam grooves 4c, 5c, and the clutch body 5 The frictional surface 5 d of the clutch body 5 is pressed against the friction surface 3 d of the second rotating shaft 3 while being kept away from the fixed ring 4 against the urging force. At this time, since the centrifugal force does not act on the brake shoes 10, 11, the projections 10 a, 11 a of the brake shoes 10, 11 are pulled by the tension elasticity of the tension spring 13 so that the outer peripheral surface of the cylindrical portion 5 a of the clutch body 5 is formed. , And the friction torque makes the clutch body 5 immovable in the axial direction. For this reason, the first rotating shaft 2 and the second rotating shaft 3 are integrally rotated synchronously, that is, the first rotating shaft 2 and the second rotating shaft 3 are connected to be able to transmit rotational power from the first rotating shaft 2 to the second rotating shaft 3.
[0020]
Here, by inputting rotational power to the first rotating shaft 2, the above-described connection state is maintained until the rotating speed of the first rotating shaft 2 exceeds a predetermined rotating speed, but the rotation speed exceeds the predetermined rotating speed. Then, the centrifugal force acting on the brake shoes 10, 11 overcomes the tension elasticity of the tension spring 13, so that the brake shoes 10, 11 open radially outward, and the protrusions 10a, 11a is separated from the outer peripheral surface of the cylindrical portion 5a of the clutch body 5. Thereby, the clutch body 5 is moved in a direction approaching the fixed ring body 4 by the resilient urging force of the disc spring 7, and the rotation speed of the clutch body 5 is lower than that of the fixed ring body 4 and the first rotating shaft 2. Become. Therefore, the cam groove 4c of the fixed ring 4 is displaced to one side in the circumferential direction with respect to the cam groove 5c of the clutch body 5, and as shown in FIG. Located on the part. As a result, the friction surface 5d of the clutch body 5 is separated from the friction surface 3d of the second rotation shaft 3, and the second rotation shaft 3 rotates relative to the first rotation shaft 2, that is, the first rotation shaft 2 From the second rotating shaft 3 to the cutting state in which the rotational power is not transmitted.
[0021]
From such a state, when the number of rotations of the first rotating shaft 2 drops below a predetermined value and the tension elasticity of the tension spring 13 exceeds the centrifugal force acting on the brake shoes 10 and 11, the brake shoes 10 and 11 have a diameter. Since the projections 10a and 11a are closed inward in the direction and are pressed against the outer periphery of the cylindrical portion 5a of the clutch body 5, the rotational speed of the clutch body 5 is slower than that of the fixed ring body 4 due to the friction torque. As a result, the clutch ball 6 is located at the shallow portion of the two cam grooves 4c, 5c, and the clutch body 5 is moved away from the fixed ring body 4 against the elastic biasing force of the disc spring 7. Therefore, the friction surface 5 d of the clutch body 5 is pressed against the friction surface 3 d of the second rotating shaft 3. For this reason, the second rotating shaft 3 is integrated with the first rotating shaft 2 so as to rotate synchronously, that is, a connection state in which rotational power is transmitted from the first rotating shaft 2 to the second rotating shaft 3.
[0022]
Contrary to the above, when the second rotating shaft 3 is set as the input side and the first rotating shaft 2 is set as the output side, the connection state and the disconnected state can be switched in the same manner as described above.
[0023]
As described above, the clutch device 1 automatically switches between the connected state and the disconnected state using the brake shoes 10 and 11 that operate by centrifugal force. It has a much simpler configuration, and can contribute to a reduction in initial cost and running cost, for example, because a device for controlling the operation of the electromagnetic brake and electric power for the operation control are not required.
[0024]
8 to 10 show another embodiment of the present invention. In this embodiment, the cylindrical portion 5a of the clutch body 5 is eliminated, and a through hole 3e penetrating in the radial direction is provided at one circumferential position in the region of the friction surface 3d in the cylindrical portion 3b of the second rotary shaft 3, and A cylindrical centrifugal friction member 15 is slidably housed in the hole 3e, and a cylindrical coil spring 16 is arranged on the outer diameter side of the centrifugal friction member 15; I have. Note that a conical coil spring 7a is used instead of the disc spring 7.
[0025]
The operation in this case will be described. First, when the first rotary shaft 2 is not rotating, the clutch balls 6 are located in the shallow portions of the two cam grooves 4c, 5c, and the clutch body 5 resists the elastic biasing force of the conical coil spring 7a. As a result, the friction surface 5d of the clutch body 5 is pressed against the friction surface 3d of the cylindrical portion 3b. Thus, the first rotating shaft 2 and the second rotating shaft 3 are in a connected state. At this time, since the centrifugal force is not acting, the centrifugal friction member 15 elastically urged by the cylindrical coil spring 16 is pressed against the friction surface 5 d of the clutch body 5. Therefore, the friction surface 5d of the clutch body 5 does not slip on the friction surface 3d of the cylindrical portion 3b, and the connection state is maintained.
[0026]
When the first rotary shaft 2 and the second rotary shaft 3 are rotated at a predetermined rotation speed or more in this state, the centrifugal force causes the centrifugal friction member 15 to be displaced radially outward while compressing the cylindrical coil spring 16, thereby causing the clutch body to move. 5 away from the friction surface 5d. As a result, the elastic urging force of the conical coil spring 8a overcomes the friction torque between the friction surface 5d of the clutch body 5 and the friction surface 3d of the cylindrical portion 3b, so that the clutch body 5 pivots toward the fixed ring 4 side. As a result, the clutch ball 6 moves to a deep portion of the two cam grooves 4c, 5c, and the friction surface 5d of the clutch body 5 is separated from the friction surface 3d of the cylindrical portion 3b. Therefore, a cutting state in which the rotational power is not transmitted from the first rotating shaft 2 to the second rotating shaft 3 is established.
[0027]
By the way, conditions for realizing the operation of each of the above embodiments will be described.
[0028]
Ti: input side torque To: output side torque Ni: input side rotation speed No: output side rotation speed Tf: friction torque generated on the input side (dragging torque)
Fc1: Force for pressing the clutch body 5 against the friction surface 3d by the cam mechanism in the disconnected state (cam pressing force).
Fc2: Force for pressing the clutch body 5 against the friction surface 3d by the cam mechanism in the connected state (cam pressing force).
Fs1: Reaction force of the disc spring 7 (cone coil spring 7a) in the cut state Fs2: Reaction force of the disc spring 7 (cone coil spring 7a) in the connected state Ts1: taking into account the reaction force of the disc spring 7 (cone coil spring 7a) in the cut state Friction torque Ts2 of brake shoes 10, 11 applied: friction torque of brake shoes 10, 11 taking into account the reaction force of disc spring 7 (conical coil spring 7a) in the connected state rc: rotation radius θc of cam groove: circumference of cam groove The occupation angle in the direction (1) The condition for maintaining the cutting state will be described.
[0029]
Ni = 0, To = 0
Fc1 = (Tf + Ts1) / (rc · tan θc) <Fs1 (1)
Tf> Ts1… ▲ 2 ▼
(2) The condition for maintaining the connection state will be described.
[0030]
Ni = No ≠ 0, Ti = To ≠ 0, Ti> Tf
Fc2 = Ti / (rc · tan θc)> Fs2 (3)
(3) Conditions for switching from the disconnected state to the connected state will be described.
[0031]
Fc1> Fs1 ... 4
Fc2> Fs2 (immediately before the contact of the friction surfaces 3d and 5d) ... [5]
Ti> Ts1 ... ▲ 6 ▼
Ti> Ts2 (immediately before contact between the friction surfaces 3d and 5d)... (7)
(4) The conditions for switching from the connected state to the disconnected state will be described.
[0032]
Fc2 = (Tf + Ts2) / (rc · tan θc) <Fs2 (8)
Fc1 <Fs1 ... [9]
Note that the present invention is not limited to only the above-described embodiment, and various applications and modifications are possible.
[0033]
(1) In the above-described clutch device 1, for example, in a hybrid car having two kinds of power sources of an engine and a motor of an automobile, the front wheels are driven by the engine power until the traveling speed of the automobile reaches a certain speed. And a four-wheel drive mode in which the rear wheels are driven by the motor power, and when the running speed of the vehicle exceeds a certain speed, transmission of the motor power to the rear wheels is cut off to form a front two-wheel drive mode. Can be used for
[0034]
(2) The cam grooves 4c and 5c of the above embodiment can be formed to have a gradually reduced shape only in one circumferential direction. In this case, the pair of cam grooves 4c and 5c need to be arranged in circumferentially opposite directions. In such a configuration, it is necessary to rotate the first rotary shaft 2 serving as the input shaft to only one of them.
[0035]
(3) In the above embodiment, the disc spring 7 of the clutch device 1 can be similarly implemented by using a conical coil spring, a cylindrical coil spring, or the like.
[0036]
【The invention's effect】
In the present invention, the switching between the connected state in which the rotational power is transmitted between the first rotary shaft and the second rotary shaft and the disconnected state in which the rotational power is not transmitted is automatically performed by the centrifugal friction member that operates according to the centrifugal force. Thus, the configuration can be simplified and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a connected state of a clutch device according to an embodiment of the present invention; FIG. 2 is a cross-sectional view showing a disconnected state of the clutch device of FIG. 1; FIG. FIG. 4 is a perspective view of a fixed ring body and a clutch body of FIG. 1. FIG. 4 is a perspective view of a fixed ring body and a clutch body of FIG. FIG. 7 is an enlarged view of a main part showing a connected state of the cam mechanism. FIG. 7 is an enlarged view of a main part showing a cut state of the cam mechanism in FIG. 2; FIG. 9 is a sectional view showing a disengaged state of the clutch device of FIG. 1; FIG. 10 is a sectional view taken along line (10)-(10) in FIG. 8;
DESCRIPTION OF SYMBOLS 1 Clutch device 2 1st rotating shaft 3 2nd rotating shaft 3d Friction surface of 2nd rotating shaft 4 Fixed ring 4c Cam groove 5 of fixed ring 5 Clutch body 5c Cam groove 5d of clutch body Friction surface of clutch body 6 For clutch Ball 7 Disc spring 10, 11 Brake shoe

Claims (2)

A clutch device that switches between a connected state in which rotational power is transmitted between a first and a second rotating shaft disposed along the same axis and a disconnected state in which no rotational power is transmitted,
A clutch body fitted to the outer periphery of the first rotation shaft so as to be relatively displaceable in the axial direction and the circumferential direction, and having a friction surface;
A friction surface provided on the second rotation shaft, the friction surface of the clutch body being in contact with and separated from the clutch body;
An urging member that constantly urges the friction surface of the clutch body in a direction away from the friction surface on the second rotation shaft side;
A centrifugal friction member that imparts rotational resistance to the clutch body when not receiving a predetermined centrifugal force or more and does not impart rotational resistance to the clutch body when it receives a centrifugal force that is not less than a predetermined value; ,
While the centrifugal friction member applies rotational resistance to the clutch body, the friction surface of the clutch body is brought into pressure contact with the friction surface of the second rotating shaft to establish the connection state, and And a cam mechanism that separates the friction surface of the clutch body from the friction surface of the second rotating shaft to bring the friction member into the disconnected state when a frictional member does not impart rotational resistance to the clutch body. The cam mechanism includes a fixed ring that is axially adjacent to the outer end of the first rotary shaft and is closer to the outer end than the clutch body and that is fixedly fitted in the axial direction and the circumferential direction, and the fixed ring and the clutch. Cam grooves which are provided at several places on the surface facing each other in the body and whose groove depth is set to be gradually smaller at least in one circumferential direction, are interposed between the two cam grooves so as to be rollable in the circumferential direction. Including clutch balls,
When the clutch ball is located at a deep portion of the two cam grooves, the clutch body is moved closer to the fixed ring to separate the two friction surfaces, while the clutch ball is shallow of the two cam grooves. 2. The clutch device according to claim 1, wherein when located at the portion, the clutch body is moved away from the fixed ring body to press the friction surfaces against each other. 3.

Images