JPH083716Y2 - Fail-safe device for turbo retarder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a turbo retarder in which an air compressor for braking the engine is attached to the drive shaft of the engine, and more particularly to a connection between the air compressor and the drive shaft. The present invention relates to a fail-safe device for a turbo retarder formed so as to be broken when an overload acts on a drive shaft.

[Prior Art] As a braking device for braking a vehicle, the present applicant has previously proposed "turbo retarder" (Japanese Patent Application No. 63-273021, etc.).

This turbo retarder is configured so that an air compressor is attached to the crankshaft of the engine so that it can be freely input and output, and the energy absorbed by the air compressor is used as the braking force of the engine. By reducing the opening of the throttle valve, the absorbed energy is reduced and the braking force is reduced.

However, in the proposal, a chain tensioner is not attached to the transmission chain that transmits power from the crankshaft to the air compressor, so stability at high speed is lacking, and the air compressor is intermittently connected to the crankshaft. Therefore, when the clutch is provided, the absorbed energy increases due to the instantaneous operation of the clutch, which may adversely affect the retarder main body and the vehicle and cause a shock. This shock is not preferable because it is felt as discomfort for the driver.

On the other hand, there is a risk that the retarder or the engine will have some trouble and the absorption torque will become excessive, or that the control operation of the throttle valve will become impossible due to the trouble of the control system or the damage of the valve itself, and the absorption torque cannot be controlled. Therefore, the applicant of the present invention reduces the rotational speed of the air compressor or reduces the absorption torque by disengaging the clutch or absorbing the shock when the retarder suddenly operates or generating excessive torque due to an abnormality in the power transmission system. In order to maintain the engine, the air compressor and the power transmission system, an output shaft is connected to the air compressor via a clutch, and a transmission chain is wound around the output shaft and the engine drive shaft. Has proposed a "turbo-retarder fail-safe device" (Japanese Patent Application No. 1-108774) provided with a controller for turning the clutch into a half clutch or a disengagement when the tension value exceeds a predetermined value.

[Problems to be solved by the invention] However, the present applicant does not make the system complicated by forming the clutch to automatically slide when excessive torque is generated without monitoring excessive torque by the transmission chain. It has been found that a fail-safe device can be inexpensively constructed.

An object of the present invention is to provide a fail-safe device for a turbo retarder, which can automatically slip a clutch to protect a power transmission system from excessive torque when clutch excessive torque that connects an output shaft and an air compressor is generated. is there.

[Means for Solving the Problems] In order to achieve the above object, the present invention connects a braking air compressor and an output shaft via a multi-plate clutch, and uses a clutch plate material of the clutch as dynamic friction and static friction. It is made of a material having a similar coefficient.

[Operation] If the material of the rotating side clutch plate that constitutes a multi-plate clutch and the fixed side clutch plate that is pressed against this to enable power transmission is made of materials with similar dynamic friction coefficient and static friction coefficient, excessive torque When they occur, relative slip between these clutch plates automatically occurs and excessive torque is automatically absorbed.

If the clutch plates are made of materials with similar dynamic friction coefficients and static friction coefficients, the shock during clutch meet is reduced.

[Embodiment] A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

First, the configuration of the turbo retarder will be briefly described. The turbo retarder is configured by attaching a speed increasing mission (not shown) to a centrifugal air compressor 1, and the air compressor 2 is rotatably installed in a radial-shaped impeller casing 3 (not shown). Housing) and the casing 3 on the rear axle of the impeller.
The wing wheel shaft 4 penetrating through is integrally attached. The impeller casing 3 has a suction port 5 for sucking air,
And a discharge port 6 for discharging compressed air,
A throttle valve (not shown) for adjusting the amount of intake air is attached to the suction port 5. The throttle valve is formed integrally with a valve body and a support shaft, and a lever attached to the support shaft is operated by an air cylinder (not shown) to adjust the opening degree of the throttle valve of the suction port 5. A load acting on the air compressor 1 according to the opening is applied as a braking force of the crankshaft 7 to brake the engine. The impeller shaft 4 is configured to be connectable to the output shaft 13 via a clutch (described later), and the power from the crankshaft 7 is interrupted by the engagement / disengagement of the clutch. The clutch 8 is provided in another casing 9 integrally connected to the impeller casing 3 so as to be movable in the axial direction and to prevent rotation, and a clutch case 10 is provided, and an inner surface of the clutch case 10 is spaced apart in the axial direction. A plurality of clutch plates 11 are spline-fitted so as to be movable in the axial direction and prevented from rotating, and the rotary clutch plates 12 respectively disposed between the output shaft 13 and adjacent clutch plates 11 are integrated. The clutch plate 10 and the air tube 14 for expanding the clutch plate 11 by the supply of the working fluid to urge the clutch plate 11 to move the clutch plate 11 to the clutch plate 12 of the output shaft 13 for clutch engagement. Is configured.

By the way, the clutch plate 11 integrated with the clutch case 10 is
Also, the material of the clutch plate 12 integrated with the output shaft 13 is formed of a material having similar dynamic friction coefficient and static friction coefficient. Specifically, a material having a dynamic friction coefficient μs and a static friction coefficient μf ₁ of μf ₁ = 1.2 to 1.4 and μs = 1 is selected. There is a graphite material as a material that satisfies this condition.

For reference, the static friction coefficient μf ₁ of the clutch plate, which has been conventionally studied, is 1.5 to 3, the dynamic friction coefficient μs is 1.5 to 3, and the static friction coefficient μf ₁ is 1.

An air supply pipe 16 branched from an air tank 19 is connected to the compressed air introduction port 15 of the air tube 14. The air supply pipe 16 has a controller 17 at an intermediate position.
A three-way solenoid valve 18 with an atmosphere opening port whose opening and closing is controlled by is attached. The controller 17 basically opens the three-way solenoid valve 18 to supply the compressed air of the air tank 19 into the air tube 14 to expand the air tube 14, and the clutch case 10 with respect to the clutch plate 12 of the output shaft 13. The clutch plate 11 is pressed, and the pressing force at this time is adjusted so that the coefficient of static friction μf ₂ in actual use is μf ₂ = μf ₁ × (1.1 to 1.2).

In other words, the coefficient of static friction μf ₂ when excessive torque is generated is 1.3 ~
The value is 1.7, and the clutch 8 slips completely with this static friction coefficient μf ₂ .

The controller 17 is basically configured to execute the control contents shown in FIG.

That is, the rotation speeds from the rotation sensors 20 and 21 installed to detect the rotation speeds of the impeller shaft 4 and the output shaft 13 are compared with each other to determine whether the clutch 8 has a relative slip or not at a determination 22. If there is relative slip, in step 23 the degree of slip is determined from the difference in the number of revolutions corresponding to that slip.
If the slip corresponds to the slip of the excessive torque as a result of this determination, at step 24, the atmosphere opening port of the solenoid valve 18 is opened to disconnect the clutch 8 to release the driving force transmission system from the overload. Then, the process goes to step 25 to notify the driver of the abnormality warning by using a warning light or an alarm. In other words, in this embodiment, by approximating the static friction coefficient and the dynamic friction coefficient of the clutch plates 11 and 12 to each other, when excessive torque is generated, the clutch plates 11 and 12 are automatically caused to slide relative to each other. Therefore, as a safety measure in the event that the clutch plates 11 and 12 are seized with each other, the relative slip of the clutch 8 is actually monitored and dealt with. Note that it is naturally possible to use the torque sensor 26 that detects the twist of the shaft as the torque as another means for detecting the relative slip.

In the embodiment, air is used to operate the clutch 8, but hydraulic oil may be used. in this case,
The air tank is configured as an oil tank to return the used operating oil to the oil tank.

[Effects of the Invention] As is clear from the above description, the present invention exerts the following excellent effects.

The braking air compressor and the output shaft were connected via a multi-plate clutch, and the material of the clutch plate of this clutch was made of a material whose dynamic friction coefficient and static friction coefficient were similar to each other. Relative slip will automatically occur in the. As a result, damage to the power transmission system including the retarder and the engine can be automatically prevented without malfunction during engine braking.

[Brief description of drawings]

FIG. 1 is a system diagram showing a preferred embodiment of the present invention, and FIG.
It is a flow chart which shows the example of control of a figure controller. In the figure, 1 is an air compressor, 8 is a clutch, and 13 is an output shaft.

Claims (1)

[Scope of utility model registration request] 1. A turbo retarder in which a braking air compressor and an output shaft are connected via a multi-plate clutch, and a material of a clutch plate of the clutch is formed of a material having a dynamic friction coefficient and a static friction coefficient which are close to each other. Fail-safe device.