JPS62200040A - Retarder for automobile - Google Patents

Abstract

PURPOSE:To prevent the circulation of cooling water at a time when cooling is unnecessary, by bypassing the cooling water in the case where temperature in a hydraulic retarder is low. CONSTITUTION:Oil circulating through the inside of a retarder 5 is cooled by a retarder radiator 17 so as not to cause the temperature to go up unduly. This radiator 17 is connected to a radiator 19 for an engine 1 via a cooling water pipe 18. And, a branch pipe 20 is connected to this cooling pipe 18, while a selector valve 21 is attached to a branch part of this pipe 20. This selector valve 21 bypasses the cooling water when temperature in the retarder 5 is low, thus wasteful cooling is prevented from being done.

Description

[Detailed description of the invention]

Field of the Invention The present invention relates to a retarder for braking a vehicle, which generates braking force by converting kinetic energy into heat, and absorbs this heat with cooling water. Related to a retarder.K Prior Art] In order to brake an automobile, as shown in Publication of Utility Model Publication No. 42-3930, Publication of Utility Model Publication No. 44-16887, etc.,
Various types of retarders have been proposed or put into practical use. Among these retarders, for example, a hydraulic retarder can be constructed relatively compactly and can provide a large braking force. Therefore, such retarders have been conventionally employed in large vehicles such as buses. And the hydraulic retarder is the oil fluid 11 that accompanies the rotation of the rotor! ! Since the braking effect is obtained by absorbing torque by I, the temperature of the oil rises when the braking force is generated. When the temperature of the oil, which is the working fluid of the hydraulic retarder, rises, its viscous resistance decreases, making it no longer possible to generate the required braking force. Therefore, conventionally, this type of retarder is provided with a radiator, and the oil is cooled by this radiator. This radiator is connected to an engine radiator, and the retarder radiator is cooled by engine cooling water. According to such a conventional retarder working oil cooling method, the retarder working oil is constantly cooled by engine cooling water via the retarder radiator. Therefore, even when the temperature of the working oil is low, further cooling is performed. If the temperature of the working oil drops more than necessary, the fluid friction of the oil within the retarder will increase, producing a braking force greater than the set value and applying force greater than the set value to the drive system. Furthermore, even in retarders other than hydraulic retarders that convert the kinetic energy absorbed by the retarder into heat, engine cooling water is transferred to the retarder or its radiator in order to cool the retarder. I was trying to circulate it. Therefore, with this configuration, even when the retarder is not activated and its temperature is low, or when hot working fluid is not circulating in the radiator, engine cooling water is not wasted inside the radiator. There was the inconvenience that it circulated. Therefore, with such a conventional retarder, there is a possibility that cooling is performed in vain. KObject of the Invention The present invention has been made in view of the above problems, and an object of the present invention is to provide a retarder that does not further cool the retarder when the temperature of the retarder is low. be.

Structure 1 of the Invention The present invention provides a retarder that generates braking force by converting kinetic energy into heat and absorbs this heat with cooling water, in which a switching valve is provided in a pipe line that supplies the cooling water. The invention relates to a retarder for an automobile, characterized in that the cooling water is bypassed by the switching valve when the temperature of the retarder is low, whereby the cooling water is further bypassed when the temperature of the retarder is low. This circulation prevents unnecessary cooling. [Embodiment] The present invention will be described below with reference to an illustrated embodiment. FIG. 1 shows a drive system of an automobile equipped with a hydraulic retarder according to an embodiment of the present invention. Transmissions 1 to 3 are attached via the . The output side of this transmission 3 is connected to a hydraulic retarder 5 via a propeller shaft 4.
The output side of the hydraulic retarder 5 is connected to the differential gear bag via the second propeller shaft 6! ! It is connected to 7. And this differential gear bag! The drive wheels are driven by an axle 8 extending left and right from the wheel 17, and are arranged in a row. The hydraulic retarder 5 attached to this drive system includes a stator 9 as shown in FIG.
A shaft 12 rotatably supported by 1 is inserted. A rotor 13 is fixed to the shaft 12, and blades formed on the end face of the rotor 1.3 face pockets of a guide plate 14 provided on the stator 9. The retarder 5 is supplied with oil from an oil supply port 15, circulates in the direction shown by the arrow, and is discharged to the outside through an oil discharge port 16. The oil circulating inside the retarder 5 in this way is
In order to prevent its temperature from rising excessively, it is cooled by a retarder radiator 17 shown in FIG. This radiator 17 is connected to an engine radiator 19 provided on the front side of the engine 1 via a cooling water pipe 18. and cooling pipe 1
A branch pipe 20 is connected to the pipe 8, and a switching valve 21 is attached to the branch portion of the pipe 20. A water pump 33 for forced circulation of cooling water is loosely connected to the cooling via 18. As shown in FIG. 3, the switching valve 21 has an inlet port 22 and an outlet port 23 in its cylinder, and a branch port 24 in a direction perpendicular to these. A cooling water passage 26 is formed in the valve body 25 rotatably disposed within the cylinder, and a recess 27 is formed so as to be continuous with this passage 26. Further, a branch passage 28 is formed by branching off from the cooling water passage 26 . Next, the operation of this retarder 5 having the above configuration will be explained. When obtaining braking force using this retarder 5, hydraulic oil is introduced into this retarder 5 through the oil supply port 15 using a hydraulic pump (not shown), and the inside is filled with the hydraulic oil.
The oil enters through the oil outlet 5 and circulates inside the oil outlet 16 to be discharged. In this state, when the rotor 13 fixed to the shaft 12 connected to the propeller shaft 4.6 is rotated, the blades formed on the rotor 13 and the pockets formed on the guide plate 14 cause the working oil to become fluid. Creates friction and absorbs torque,
This will generate braking force. This therefore causes the vehicle to be braked and decelerated. When the retarder 5 is operated as described above, the temperature of the working oil increases due to friction within the working oil. Therefore, this working oil is circulated within the radiator 17 shown in FIG. When the water pump 33 is driven, engine cooling water is supplied to the radiator 17 from the radiator 19 via the cooling via 18, thereby cooling the working oil. That is, at this time, the switching valve 21 is switched as shown in FIG. 3, and the inlet 22 and outlet 23 are aligned with the inlet and outlet of the cooling water passage 26 of the valve body 25, respectively. Therefore, the cooling water is
As shown, the oil is supplied from the engine radiator 19 to the retarder radiator 17, and the retarder radiator 17 reliably cools the working oil. Therefore, a decrease in braking force due to an increase in the temperature of the working oil is prevented. On the other hand, if the temperature of the working oil in the retarder 5 is sufficiently low and there is no need to perform further cooling fill, the temperature sensor 29 detects this, and the controller 30 switches the switch provided in the via 18. The valve 21 is switched as shown in FIG. In other words, this switching valve 2
The first valve body 25 is rotated counterclockwise as shown in FIG. Then, the inlet 22 and branch port 24 of this switching valve 21 are connected to the recess 27 of the valve body 25 and the branch passage 2, respectively.
8, and the outlet 23 of the switching valve 21 is closed. Therefore, the water supplied from the engine radiator 19 will flow into the branch pipe 20 as shown by the arrow 32 in FIG. 1, and the cooling water will be bypassed. That is, since the supply of cooling water to the retarder radiator 17 is cut off, the cooling operation in the retarder radiator 17 is no longer performed. Therefore, it is possible to prevent the working oil of the retarder 5 from being cooled more than necessary, and it is possible to prevent the braking force of the retarder 5 from becoming abnormally higher than the set value, thereby protecting the drive system. becomes possible. Although the present invention has been described above with reference to the illustrated embodiment, the present invention is not limited to the above embodiment, and various modifications can be made based on the technical idea of the present invention. For example, although the above embodiment relates to a hydraulic/hydraulic retarder, the present invention is applicable to various other types of retarders, in which the energy absorbed by the retarder is converted into heat, and this heat is absorbed by cooling water. Applicable to all retarders.

【Effect of the invention】

As described above, in the present invention, a switching valve is provided in the pipe line that supplies cooling water, and the switching valve bypasses the cooling water when the temperature of the retarder is low. Therefore, it is possible to prevent circulation of cooling water even when cooling is not necessary, and to omit unnecessary cooling.

[Brief explanation of drawings]

FIG. 1 is a plan view of a main part of a drive system of an automobile equipped with a hydraulic retarder according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing a hydraulic retarder provided in this drive system, and FIG. The figure is a sectional view showing the structure of a switching valve for supplying cooling water to the retarder radiator, and FIG. 4 is a sectional view of the switching valve in the switched state. In addition, in the symbols used in the drawings, 5...Hydraulic retarder 17...Retarder radiator 18...Cooling water pipe 21...Switching valve 25...Valve body 26...Cooling water passage 28...This is a branch passage.

Claims (1)

[Claims] In a retarder that generates braking force by converting kinetic energy into heat and absorbs this heat with cooling water, a switching valve is provided in the conduit that supplies the cooling water, and when the temperature of the retarder is low. A retarder for an automobile, characterized in that the cooling water is bypassed by the switching valve.