JPS63111322A - Friction clutch - Google Patents

Abstract

PURPOSE:To prevent the shock upon rapid engagement of the clutch, by quickly displacing a piston until it comes to contact with a driving friction plate, and then slowly displacing the piston. CONSTITUTION:Until a piston 151 comes to contact with a driving friction plate 180, a biasing force only of a first spring 200 is applied to the piston 151. When the piston 151 is displaced in a predetermined quantity or more to contact the driving friction plate 180, a given biasing force of a second spring 201 is addition to the biasing force of the first spring 200 is applied to a rear surface of the piston 151. Under the condition, a displacement speed of the piston 151 is relatively slow, so that rapid collision of the driving friction plate 180 against a driven friction plate 220 may be prevented. Accordingly, rotation of a driving shaft 100 is gradually transmitted to a driven shaft 230, thereby suppressing shock at starting of a compressor.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a friction clutch, and is effective when used, for example, to transmit the rotational driving force of an automobile engine to a refrigerant compressor for an automobile air conditioner.

[Conventional technology and its problems]

Conventionally, it has been proposed to use a friction clutch as a means for transmitting power to a compressor for an automobile air conditioner. In this type of friction clutch, a driving-side friction plate is disposed on a driving-side shaft so as to be movable in the axial direction, while a temporary driven-side clutch is fixed to a driven-side shaft. The displacement of the piston causes the drive-side friction plate to be displaced in the direction of the driven-side friction plate, thereby transmitting the rotational force of the drive-side shaft to the driven-side shaft.

In such friction clutches, the piston is displaced by controlling the hydraulic pressure applied to a pressure chamber formed at the tip of the piston. Additionally, a spring was placed on the back of the piston to push the piston back when the supply of hydraulic pressure to the pressure chamber was cut off.

Here, the spring disposed on the back surface of the piston is required to have a predetermined load so that the piston will not be displaced due to malfunction. Furthermore, if the load of this spring is small, the piston will be suddenly displaced, causing a situation in which the driving-side friction plate will momentarily come into contact with the driven-side friction plate. Therefore, in conventional pistons, the spring disposed on the back surface of the piston needs to have a predetermined size.

However, in this state where the large spring on the back of the piston is constantly biased with a large load, even if signal pressure is input to the pressure chamber, there will be a delay in response until the clutch is actually connected. becomes.

[Problem to be solved by the invention]

The present invention has been devised in view of the above points, and an object of the present invention is to enable the driving-side friction clutch to gradually come into contact with the driven-side friction clutch when the clutch is connected. Another object of the clutch of the present invention is to enable the clutch to be connected immediately when a signal pressure is input to the pressure chamber.

In other words, in the present invention, the piston is displaced at a relatively high speed until it contacts the drive side friction plate, and after the piston contacts the drive side friction plate, the piston is displaced at a relatively slow speed. The purpose is to enable the driving side friction plate to gradually come into contact with the driven side friction plate.

[Configuration and operation]

In order to achieve the above object, in the compressor of the present invention, the spring disposed on the back surface of the piston has the following configuration. In other words, when the displacement of the piston is below a predetermined value, the biasing force applied to the back surface of the piston is relatively small, and when the piston is displaced beyond a predetermined value, a large biasing force can be applied to the back surface of the piston. It shall be.

By arranging a spring having the above characteristics, it is possible to switch the displacement speed of the piston into two stages. That is, the piston can be rapidly displaced until it comes into contact with the drive-side friction plate, and then the drive-side friction plate can be displaced slowly in the direction of the sliding-side friction plate.

〔Effect of the invention〕

With the above configuration, the clutch of the present invention can be connected to the input signal without delay in response. Furthermore, with the clutch of the present invention, power is gradually transmitted when the clutch is engaged, and shocks caused by abrupt engagement are prevented.

〔Example〕

An embodiment of the clutch of the present invention will be described below based on the drawings.

In Fig. 1, 100 is a drive shaft with a rotating t at its end.
The zero-rotation plate N101 is identified by the bolt 102 and is connected to the boot I7103, and receives the rotational driving force of the automobile engine through a belt (not shown). The pulley 103 is rotatably supported by a bearing 104, and the bearing 104 is fixed on the front housing 106 by a circlip 105.

A shaft sealing device 107 is disposed on the inner surface of the front housing 106 to prevent internal lubricating oil, refrigerant, etc. from leaking along the shaft 100.

A pump housing 120 is disposed on the side of the front housing 106, and an oil suction chamber 121 and an oil discharge chamber 122 are formed in this pump housing. Further, a pump rotor 126 is fixed on the shaft 100, and a trochoid pump 130 is constituted by this pump rotor 126, the above-mentioned oil suction chamber 121, oil discharge chamber 122, etc. Oil suction chamber is suction passage 1
It communicates with the oil tank 132 via 31. Similarly, the oil discharge chamber 122 also communicates with the oil tank 132 via a discharge passage 133. Further, a solenoid valve 140 is disposed in the middle of the discharge passage 133, and the opening and closing of the discharge passage 133 is controlled by this solenoid valve 140.

The oil discharge chamber 122 is connected to the cylinder 150 and the piston 151 through a pressure guiding passage 140 formed in the shaft lOO.
It also communicates with a pressure chamber 153 formed between.

The cylinder 150 is fixed on the shaft 100,
It rotates together with the shaft. Also piston 15
1 is slidably disposed within the cylinder 150. This piston 151 is engaged with a pin 160 fixed to the cylinder 150, and rotates together with the cylinder 150.

There is an O-ring 16 between the piston 151 and the cylinder 150.
1.162 maintains the seal.

A clutch holding plate 170 is mounted on the shaft 100 with the bolt 1
71, and this holding plate 170 rotates together with the shirt 100. A drive-side friction plate 180 is slidably disposed on the holding plate 170. This drive-side friction plate is displaceable in the axial direction of the shaft and is spline-coupled to rotate integrally with the shaft. A plurality of drive side friction plates 180 are arranged, and a spacer 190 is arranged between each friction plate 180. The above-mentioned piston is disposed at a position facing the drive-side friction plate 180, which is also located at the left end in the figure. A first spring 200 and a second spring 201 are provided between the retaining plate 170 and the piston 151.
is installed. As shown in FIG. 2, the first spring 200 has a smaller urging force than the second spring 201. Further, both ends of the first spring 200 are always in contact with the piston 151 and the retaining plate 170, but the ends of the second spring 201 are in contact with the retaining plate 170.
It is designed to come into contact only with 70.

That is, the piston 151 moves a predetermined amount to the drive side friction plate 180.
When the piston 151 is displaced in this direction, the inner wall 159 of the piston 151 and the end of the second spring 201 can come into contact with each other.

Therefore, the biasing force of the spring applied to the piston 151 is as shown in FIG. When the stroke of the piston is within a predetermined value, for example, 2.5 strokes, the inner surface 15 of the piston 151
9 is not in contact with the second spring 201. Therefore, during the displacement during this period, only the biasing force a from the first spring 200 is applied to the piston 151. If the piston 151 is displaced by a predetermined value or more, the biasing force of the second spring 201 is applied to the piston 151. As a result, the relationship between the piston stroke and the spring force applied to the piston 151 changes as shown in FIG.

The driving side friction plate 180 is arranged to face the driven side friction plate 220, so when the driving side friction plate is displaced by a predetermined value or more, the contact resistance between the driving side friction plate and the driven side friction plate becomes large. do. The driven side friction plate 220 is a rotating ring 223
The rotating ring 223 is fixed to the driven shaft 230. The driven shaft 230 is disposed coaxially with the driving shaft 100, and the driven shaft rotatably supports the driving shaft 100 via a bearing 231. Further, the driven shaft 230 is rotationally supported by a bearing 241 fixed to a side plate 240.

The driven shaft 230 is integrally formed with the rotor 235, so when the driven shaft 230 rotates, the rotor 235 also rotates within the compressor housing 250. A vane groove 237 is formed in the rotor 235,
A vane 239 is slidably disposed within this vane groove.

The center of rotation of the rotor is displaced from the center of the housing 250 by a predetermined amount, and therefore the volume of the compression chamber 270 formed by the outer surface of the rotor 235, the inner surface of the housing 250, and the side surface of the vane 239 changes as the rotor 235 rotates.

A suction hole is opened in a portion of the side plate 240 that faces the volume expansion position of the compression chamber 270.
The refrigerant in 80 is guided to compression chamber 270.

A discharge hole is opened in a portion of the housing 250 that faces the position where the volume of the compression chamber 270 is the smallest, and discharges the refrigerant compressed in the compression chamber to the discharge chamber 281 . Further, a communication hole on the discharge side is opened in the end plate 290, and the discharge chamber communicates with a discharge passage chamber 296 formed in the rear housing 295.

The discharge passage chamber also separates oil, where lubricating oil is separated from the refrigerant. The refrigerant from which the lubricating oil has been separated is discharged to the condenser side of a refrigeration cycle (not shown).

The operation of the apparatus having the above configuration will be explained below.

First, a state in which power is not transmitted to the compressor will be explained.

In this case, the solenoid valve 140 opens the discharge passage 133. Therefore, the working oil discharged from the trochoid pump 130 is returned to the oil tank 132 side by the discharge chamber 122 via the discharge passage 133. In other words, in this case, the trochoid pump 130 operates due to the rotation of the drive shaft 100, but the pump 130 operates without load, and no operating pressure is applied to the pressure chamber 153. Even if this pressure is applied to the pressure chamber 153, the spring 200 prevents the piston 151 from being displaced.

Next, when the compressor needs to be driven, the electromagnetic valve 140 closes the discharge passage 133 in response to an electric signal indicating the state.

When the discharge passage 133 is closed in this way, the discharge hydraulic pressure from the trochoid pump 130 is introduced into the pressure chamber 153 via the pressure guiding passage 140. The piston 151 is displaced to the right in the figure by the hydraulic pressure introduced into the pressure chamber 153.

In this case, only the biasing force is applied to the piston 151 by the first spring 200 until the piston 151 comes into contact with the drive-side friction plate 180.

Moreover, the set pressure of the first spring 200 is relatively small as shown in FIG. 3. Therefore, the piston 151 immediately begins to be displaced.

In other words, the piston 151 is displaced without a large delay after the signal is input to the solenoid valve 140.

When the piston is displaced by a predetermined value or more and the piston and the drive-side friction plate 180 begin to come into contact with each other, the second spring 201 also applies a predetermined biasing force to the back surface of the piston 151.

In this state, the hydraulic pressure applied inside the pressure chamber 153 is
Both spring 200 and second spring 201 must be pressed and displaced. Moreover, the second spring 2
01 has a large spring force as shown in FIG. Therefore, in this state, the displacement speed of the piston 151 is relatively slow.

Therefore, a situation in which the driving side friction plate 180 suddenly collides with the driven side friction plate 220 is prevented.

Therefore, the rotation from the driven shaft 100 is gradually transmitted to the driving shaft 230, and the shock at the time of starting the compressor is alleviated.

When the rotational driving force is transmitted to the driven shaft 230 in this manner, the rotor 235 is rotated by the rotational force, and the suction, compression, and discharge operations of the compressor are performed.

Note that in the above-described embodiment, the cylinder 150 is connected to the shaft 10.
Although the cylinder 150 rotates integrally with the cylinder 150, it is not necessarily necessary that the cylinder 150 rotates together with the cylinder 150.

That is, the cylinder 150 may be fixed in position within the clutch housing, and the shaft 100 may be rotatably disposed at the center of the cylinder 150 via a bearing or the like.

Further, in the above example, the second spring 201 is connected to the piston 15.
1 was disposed at a position where the biasing force was transmitted to the piston 151 from the position where the second friction plate 180 came into contact with the drive side friction plate 180. The spring 201 may be brought into contact with the inner surface 159 of the piston 151.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the clutch of the present invention;
The figure is a sectional view showing the main part of the clutch shown in FIG. 1, and FIG. 3 is an explanatory view showing the setting force of the spring shown in FIG. 2. 100... Drive side shaft, 15o... Cylinder. 151... Piston, 153... Pressure chamber, 180...
・・Drive side friction plate, 200, 201 ・・Spring,
220... Driven side friction plate, 230... Driven side shaft.

Claims (1)

[Claims] a drive-side shaft; a drive-side friction plate disposed on the drive-side shaft so as to be slidable and rotatable integrally with the drive-side shaft; a driven-side friction plate disposed opposite to the drive-side friction plate; a driven shaft that is arranged to face the driving shaft and to which the driven friction plate is fixed; a piston that is disposed on a side surface of the driving friction plate and presses the driving friction plate in the direction of the driven friction plate; The piston is slidably housed in a cylinder and a pressure chamber is formed between the piston and the piston. When the displacement of the piston in the direction of the driving side friction plate is less than a predetermined value, the piston is urged with a relatively small urging force, and when the displacement of the piston in the direction of the driving side friction plate is more than a predetermined value, a relatively large urging force is applied. A friction clutch characterized in that the piston is biased by a biasing force.