JPH01238719A - Multiple disc clutch - Google Patents

Abstract

PURPOSE:To restrain generation of abnormal noise by connecting a motor capable of being remotely controlled to a changing mechanism which presses a clutch by changing the rotary force of the motor. CONSTITUTION:The hollow shaft 93 of the rotor 91 of a motor 65 capable of being remotely controlled is fitted to the inside cylindrical portion 87 of a yoke 83 and a spiral groove is formed on an opposite face of the inside cylindrical portion 87 and the hollow shaft 93. Steel balls 95 are arranged along the spiral groove, a press ring 97 is fixed to the left end of the hollow shaft 93 and the press ring 97 is abutted to the press plate 79 of a clutch portion 63 via a needle bearing 99. Since magnetic flux such as an electromagnetic clutch does not penetrate friction plates, friction plates applied by lining and having superior friction property can be freely selected. Accordingly, at the time of operation, abnormal noise such as creaking sound or vibration sound is not generated and operation property is improved.

Description

[Detailed description of the invention] Purpose of invention] (Industrial application field) The present invention relates to a multi-disc clutch.

(Prior art) Conventionally, multi-disc clutches with adjustable fastening force include electromagnetic clutches that use the attraction force of an electromagnet to engage and release, and adjust the fastening force using the pressing force of an actuator operated by fluid pressure. Hereinafter, the clutches are typically referred to as hydraulic clutches.

Electromagnetic clutches need to use friction plates that efficiently pass magnetic flux in order to increase the attractive force and increase the clutch capacity and response speed. Therefore, in practice, the friction plate material is limited to iron plates without lining. . As shown in Figure 3,
As shown by the solid line in the graph of the friction characteristics expressed by the friction velocity ■ and the friction coefficient μ, the friction characteristics of the iron friction plate have a peak near V = O, and such fluctuations in μ cause squealing noise. vibration noise is likely to occur. As shown by the broken line in FIG. 3, it is generally desirable that the friction characteristics exhibit a gentle upward slope to the right. There are friction plates made of iron plates lined with vapor or copper-based alloys that satisfy this characteristic, but cannot be used in electromagnetic clutches because the lining layer obstructs the passage of magnetic flux. Further, in a hydraulic clutch, a hydraulic pressure generation source such as an oil pump, a conduit, an actuator, etc. are required, which causes problems such as an increase in the number of parts and an increase in the size of the device.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a multi-plate clutch that can use friction plates with good friction characteristics, has excellent operating characteristics, and has a small number of parts.

[Structure of the Invention] (Means for Solving the Problem) The multi-disc clutch of the present invention includes a cylindrical case, a hub member housed in the case so as to be relatively rotatable on the same axis, and the hub member. a clutch portion consisting of a plurality of friction plates arranged alternately and engaged with the outer periphery of the case and the inner periphery of the case separately in the rotational direction; a motor that can be externally controlled; The present invention is characterized by comprising a conversion mechanism that presses and engages the clutch.

(Operation) The conversion mechanism changes the direction of the rotational force of the motor to press and engage the clutch. By externally controlling the rotation direction and current value of the motor, it is possible to engage and release the clutch and adjust the engagement force. When the clutch is engaged, rotational input from one of the case and the hub member is output from the other at a rate corresponding to the magnitude of the engagement force of the clutch.

(Example) One embodiment will be explained with reference to FIG. 1 and FIG. 2.

This embodiment has four-wheel drive (4W) as shown in FIG.
D) It is used as a differential limiting device for the center differential housed in a car's transfer case. In the following description, the left-right direction is the left-right direction in FIG. 1, and corresponds to the front-rear direction of the vehicle.

First, power transmission in this vehicle will be explained with reference to FIG.

The rotation of the engine 1 is changed in speed by a transmission 3 and transmitted to a transfer 7 via an output shaft 5. The transfer 7 transfers the transmitted driving force to the front wheel side differential device 13 via the output shaft 9, and also to the propeller shaft 11.
The signal is transmitted to the differential device 15 on the rear wheel side. These differential devices 13.15 differentially distribute the transmitted driving force to the left and right wheels 17, 19, 21, and 23, respectively.

Next, the configuration will be explained.

The input shaft 25 is rotatably supported by a transfer case 29 by a bearing 27, and inputs the driving force of the engine from the transmission 3 through the output shaft 5. The transfer case 29 has a three-piece construction with joints 28 and 30. The output shaft 31 is connected to the input shaft 25 to the transfer case 29 by a bearing 33.
It is rotatably supported on the same axis as the propeller shaft 11 and transmits driving force to the differential device 15 on the rear wheel side. The front end of the output shaft 31 is formed in a trumpet shape, and the input shaft 25 and the output shaft 31 are connected via a needle bearing 35 so as to be relatively rotatable inside the trumpet-shaped end.

A hollow pulley 37 is coaxially mounted on the input shaft 25, and the pulley 37 is rotatably supported by the input shaft 25 by a needle bearing 39 and by the transfer case 29 by a bearing 41. Another pulley 43 is rotatably supported at one end of the transfer case 29 in the vehicle width direction by a bearing 45°47.

The rotation axes of the pulley 37 and pulley 43 are arranged parallel to each other. The pulley 43 has an output shaft (
(not shown) are connected by splines.

The surfaces of the pulleys 37 and 43 are provided with unevenness at a constant pitch, and a timing belt 49 that meshes with the unevenness connects the pulleys 37 and 43.

A carrier 53 of a planetary gear 51 is spline connected to the rear end of the input shaft 25, and a sun gear 55 that meshes with the planetary gear 51 is integrally formed on the outer periphery of the right end of the pulley 37. Further, an internal gear 57 that meshes with the planetary gear 51 is fixed to the trumpet-shaped end of the output shaft 31. In this way, a planetary gear type differential device (center differential) 59 is configured. Therefore, input shaft 2
The rotational driving force of the engine from 5 is transmitted through the carrier 53,
A sun gear 55 and an internal gear 5 meshing with the planetary gear 51, respectively.
7, pulley 37, timing belt 49,
It is transmitted to the front wheels 17° 19 through the pulley 43, and is transmitted to the rear wheels 21° 23 through the output shaft 31. Further, the differential rotation generated between the front wheels 17.19 and the rear wheels 21.23 is absorbed by the rotation of the planetary gear 51.

A multi-plate clutch 61 of the present invention, which functions as a differential limiting device for the differential device 59, is disposed inside the transfer case 29.

The electric multi-disc clutch 61 includes a clutch section 63 and a motor 65.
and a ball screw 67 which is a conversion mechanism.

The clutch portion 63 includes a cylindrical case 69, a hub member 71, and a friction plate 7 that engages with the inner peripheral surface of the case 69 in the rotation direction.
3, a friction plate 75 engaged with the outer peripheral surface of the hub member 71 in the rotational direction, and pressing plates 7v and 79 arranged on both sides of the friction plates 73 and 75. The case 69 is engaged with the sun gear 55 and positioned in the thrust direction by a stopper ring 70, and the hub member 71 is welded to the trumpet-shaped outer circumference of the output shaft 31. These friction plates 7
3.75 used iron plates with paper lining on both sides.

The motor 65 has a yoke 83 of a stator 81 fixed to the transfer case 29 with bolts 85. The yoke 83 has a double cylindrical shape, having an outer cylindrical part that holds the stator 81 and an inner cylindrical part 87 that encases the output shaft 31. The inner cylindrical part 87 is the connection part between the output shaft 31 and the input shaft 25. is rotatably supported by a bearing 89.

The hollow shaft 93 of the rotor 91 is connected to the inner cylindrical portion 87 of the yoke 83.
is cloaked in. A spiral groove is formed on the opposing surfaces of the inner cylindrical portion 87 and the hollow shaft 93, and a large number of steel balls 95 are arranged along this spiral groove.

Stoppers for preventing the steel ball 95 from falling off are provided at both ends of this spiral groove. In this way, the ball screw 67, which is a conversion mechanism, is constructed. A pressure ring 97 is fixed to the left end of the hollow shaft 93 and is in contact with a pressure plate 79 of the clutch portion 63 via a needle bearing 99.

The motor 65 may be operated manually from the driver's seat depending on the road surface conditions, or may be operated by each wheel 17, 19, 21, 23, for example.
Automatically operated based on signals from the slip sensor.

Next, the function of the multi-disc clutch 61 configured as described above will be explained. When the motor 65 is energized and the rotor 91 is rotated, the rotor 91 advances to the left by the direction changing function of the ball screw 67, and the press ring 97 While rotating, the clutch portion 63 is pressed through the needle bearing 99 to engage the clutch portion 63. When the clutch portion 63 is engaged, the output shaft 31 and the pulley 37 are connected in the differential device 59, so differential rotation therebetween is stopped or restricted. Since the torque of the motor 65 is proportional to the current value, the engagement force of the clutch portion 63 can be adjusted to an arbitrary magnitude by changing the current value. To release the clutch portion 63, the motor 65 is rotated in the opposite direction to move the rotor 91 backward to the right. In this way, the multi-plate clutch 61 functions as a differential limiting device for the differential device 59.

Furthermore, to explain this function in accordance with the performance of the vehicle, on a good road, if the clutch part 63 is released manually or automatically by sensor detection, the differential device 5
9 functions as a normal center differential and distributes the driving force between the front wheels 17 degrees 19 and the rear wheels 21 degrees 23 depending on road conditions, improving driving stability. Also, when cornering, an optimal grip balance between the front and rear wheels can be obtained, increasing steering stability. Further, since the center differential 59 absorbs the twisting that occurs in the propeller shaft 11 when making a low-speed sharp turn such as when parking the vehicle, tight corner braking does not occur.

On rough roads, e.g. front wheels 17.19 or rear wheels 21.2
If one of the wheels 3 slips and becomes stuck, the clutch 63 is engaged and the center differential 59 is locked, and driving force is sent to the other wheel, allowing the vehicle to escape from the stuck state.

According to this configuration, unlike an electromagnetic latch, magnetic flux does not pass through the friction plates 73, 75, so that a friction plate with excellent friction characteristics that is lined can be freely selected. Therefore, the maximum engagement force (capacity) of the clutch portion 63 can be designed to be large by using a friction plate having a large friction coefficient μ. Furthermore, by using a friction plate with a lining, a phenomenon corresponding to a brake fade phenomenon in which the fastening force decreases as the temperature rises does not occur. Furthermore, no abnormal noise such as squealing or vibration is generated during operation. Furthermore, since there is no hysteresis phenomenon as with electromagnetic clutches, the release time is short and the idle torque is small. In addition, it has fewer parts than a hydraulic clutch, does not require piping, and is low cost.

Note that since the rotation of the rotor 91 is less than a fraction of a rotation when the clutch portion 63 is operated, a cam mechanism can be used in combination with a return spring in addition to the ball screw 67 as the conversion mechanism.

When the multi-plate clutch 61 of the present invention is used as a differential limiting device, it can be used not only for the planetary gear type differential as in the above embodiment, but also for other types of differentials.

It can also be used for front and rear wheel differentials, and
It can also be used as a 2WD-4WD switching mechanism for a four-wheel drive vehicle. Furthermore, it goes without saying that it can be used for the same purposes as electromagnetic clutches and hydraulic clutches, not only for vehicles but in general industry.

[Effects of the Invention] As described above, the multi-plate clutch of the present invention can use various friction plates, and can suppress the generation of abnormal noise.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment together with a differential device, Fig. 2 is a schematic diagram of a drive transmission system of a vehicle using the embodiment shown in Fig. 1 and a differential device, and Fig. 3 shows the friction characteristics of the friction plate. This is a graph showing. 59...Differential device 61...Multi-plate clutch 63...Clutch section 65...Motor 67...Ball screw (conversion mechanism) 6...Case 71...Hub part removal 73.75 ...Friction plate agent Patent attorney Yasuo Miyoshi\41 37 51 -State and 55L 3953'I 0 f 1'''Jll l+==j

Claims (1)

[Claims] A cylindrical case, a hub member housed in the case so as to be able to rotate relative to each other on the same axis, and a plurality of pieces that engage with each other in the rotational direction and are arranged alternately on the outer periphery of the hub member and the inner periphery of the case. What is claimed is: 1. A multi-disc clutch comprising: a clutch portion comprising a friction plate; an externally controllable motor; and a conversion mechanism that converts the rotational force of the motor to press and engage the clutch.