JPH0689842B2 - Coolant control device for continuously variable transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling oil control device for a continuously variable transmission, and in particular, a pump loss of an oil pump is caused by switching between a clutch cooling passage and an oil cooling passage. The present invention relates to a cooling oil control device for a continuously variable transmission, which reduces the fuel consumption.

[Conventional technology]

In a vehicle, a transmission is interposed between an internal combustion engine and driving wheels. This transmission system changes the driving force of the drive wheels and the traveling speed in accordance with the traveling condition of the vehicle that changes in a wide range, and makes the internal combustion engine fully exhibit its performance. The transmission is formed between both pulley part pieces of a pulley having a fixed pulley part piece fixed to the rotary shaft and a movable pulley part piece mounted on the rotary shaft so as to be able to come into contact with and separate from the fixed pulley part piece. 2. Description of the Related Art There is a continuously variable transmission that changes the gear ratio by increasing or decreasing the radius of rotation of a belt wound around a pulley by increasing or decreasing the width of a groove to change power ratio. This continuously variable transmission is disclosed, for example, in JP-A-59-13133, JP-A-59-43249, and JP-A-59-86719.

[Problems to be Solved by the Invention] In the conventional cooling oil control device for a continuously variable transmission, the cooling oil is constantly circulated to the clutch portion in order to cool the clutch, and the temperature of the cooling oil is lowered. In order to make it possible, it is always distributed to the oil cooler.

As a result, a large oil pump that satisfies the clutch cooling oil amount for cooling the clutch and the oil cooling oil amount for lowering the temperature of the cooling oil is required, resulting in a large facility cost and economically. There is an inconvenience of being disadvantageous. Further, the cooling of the clutch is necessary only at the time of starting, and there is an inconvenience that the pump loss of the oil pump becomes large by performing the cooling of the clutch during unnecessary traveling of the vehicle.

[Object of the Invention]

Therefore, an object of the present invention is, in order to eliminate the above-mentioned inconvenience, in a belt drive type continuously variable transmission, a cooling passage for clutch cooling and oil cooling is provided, and the clutch cooling is provided in the middle of this cooling passage according to operating conditions. By providing a switching valve that switches between the oil passage and the oil cooling passage, the clutch cooling and the oil cooling are switched according to the operating conditions to reduce the pump loss of the oil pump and to reduce the size of the oil pump. It is possible to realize a cooling oil control device for a continuously variable transmission that can be realized in an economical manner.

[Means for solving problems]

In order to achieve this object, the present invention is configured to increase or decrease the width between both pulley part pieces of a fixed pulley part piece and a movable pulley part piece which is attached to the fixed pulley part piece so as to be able to come into contact with and separate from the fixed pulley part piece. In a belt drive type continuously variable transmission that changes the gear ratio by increasing or decreasing the radius of wrap of a belt to be wound, a cooling passage for clutch cooling and oil cooling is provided, and the clutch cooling is provided in the cooling passage in accordance with operating conditions. It is characterized in that a switching valve for switching operation is provided between the oil passage and the oil cooling passage.

[Action]

By configuring as described above, the operating condition, for example, the switching valve is operated at the time of starting to perform clutch cooling,
When traveling other than when the vehicle is starting, the switching valve is operated to cool the oil and reduce the pump loss of the oil pump.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 3 show an embodiment of the present invention. First
In the figure, 2 is a belt drive type continuously variable transmission, 4 is a drive side pulley, 6 is a drive side fixed pulley part piece, 8 is a drive side movable pulley part piece, 10 is a driven side pulley, 12 is a driven side fixed A pulley piece 14 is a driven side movable pulley piece. The drive side pulley 4 is a drive side fixed pulley section piece 6 fixed to the rotary shaft 16 and a drive side movable pulley section piece mounted on the rotary shaft 16 so as to be movable and non-rotatable in the axial direction of the rotary shaft 16. 8 and. Further, the driven side pulley 10 also has a driven side fixed pulley portion piece 12 and a driven side movable pulley portion piece 14 similarly to the driving side pulley 4. The drive-side movable pulley part 8 and the driven-side movable pulley part 14 have first and second
Housings 18 and 20 are mounted respectively, and the first and second hydraulic chambers 2
2 and 24 are formed respectively. At this time, in the second hydraulic chamber 24 on the driven side, the second hydraulic chamber 24 is expanded in the direction of expansion of the second hydraulic chamber 24.
A biasing means (26) including a spring for biasing the housing (20) is provided.

An oil pump 28 is provided on the rotary shaft 16, and the oil pump 28 is connected to the first and second hydraulic chambers 22 and 24 by the first and second oil passages 30 and 32, respectively, and at the middle of the first oil passage 30. A primary pressure control valve 34 for controlling the primary pressure is installed in the valve. Further, a pump pressure control valve 36 for controlling the pump pressure is connected to a first oil passage 30 on the oil pump 28 side of the primary pressure control valve 34 by a third oil passage 38, and a fourth oil passage is connected to the pump pressure control valve 36. The pump pressure (generally 5 to 25 kg / cm ² ) is kept constant by the passage 40 (1.5 to 2.0 kg).
The constant pressure control valve 42 controlled to / cm ² ) is connected. Further, the constant pressure control valve 42 is attached to the oil pump 28 and the oil pan 44 at the fifth position.
Contact by oil passage 46.

A spool type cooling switching valve 50 is connected to the constant pressure control valve 42 by a sixth oil passage 48. Then, the cooling switching valve 50 is connected to a clutch cooling passage 54 for cooling the hydraulic clutch 52, and the cooling switching valve 50 is connected to the oil cooler.
An oil cooling passage 60 communicating with the oil pan 58 via 56 is provided. At this time, throttles 62 and 64 for restricting the maximum amount of oil are provided in the clutch cooling passage 54 and the oil cooling passage 60. Further, a primary pressure introducing passage 66 for introducing the primary pressure from the first oil passage 30 on the first hydraulic chamber 22 side of the primary pressure control valve 34 is connected to the cooling switching valve 50.

A clutch pressure control valve 68 for controlling the clutch pressure is provided at the end of the second oil passage 32 opposite to the oil pump 28.
The clutch pressure control valve 68 connects the seventh oil passage 72 to operate the piston 70 of the hydraulic clutch 52. Further, the cooling switching valve 50 includes a clutch pressure control valve 68.
The clutch pressure introducing passage 74 for introducing the clutch pressure of the hydraulic clutch 52 after the passage is communicated.

Further, a control unit 76 for inputting various conditions such as the throttle opening degree of the vehicle, engine rotation, vehicle speed, and oil temperature is provided, and the control unit 76 controls the primary pressure control valve 34, the pump pressure control valve 36, and the clutch pressure control. It is configured to control the opening and closing of valve 68. Reference numeral 78 is a pressure plate, and 80 is a clutch disc.

As shown in FIGS. 2 (a) and 2 (b), the cooling switching valve 50 is provided with a spool valve 84 that reciprocates in a body 82. The spool valve 84 has a diameter D on the primary side and a diameter d on the clutch side.
The relation with is D> d. From the left side of the body 82, the primary pressure introducing passage 66, the clutch cooling passage 54, and the sixth
Oil passage 48, oil cooling passage 60, clutch pressure introduction passage
74 and the air hole 86. Further, in the body 80,
The spool valve 84 is located on the right side, that is, the sixth oil passage 48.
A spring 88 is provided to urge the oil cooling passage 60 and the oil cooling passage 60 to communicate with each other.

Next, the operation will be described.

When the vehicle is starting, the belt ratio is maintained at or near full low in order to obtain a high driving force, at which time the primary pressure is almost zero or very low. However, the clutch pressure for maintaining the half-clutch state is secured at a predetermined pressure related to the engine torque, and the clutch pressure is introduced into the cooling switching valve 50 by the clutch pressure introduction passage 70 as shown in FIG. 2 (a). It
Then, the spool valve 84 is operated against the urging force of the spring 88 that urges the sixth oil passage 48 and the oil cooling passage 60 to communicate with each other, thereby connecting the sixth oil passage 48 and the clutch cooling passage 54. To cool the clutch.

When the clutch is engaged and the vehicle reaches a running state, the belt ratio is gradually changed and the sheave pressure on the primary side increases. Then, the clutch pressure is maintained at a pressure equal to or lower than the secondary sheave pressure. At this time, since the sheave pressure receiving area on the primary side is set larger than that on the secondary side, the belt ratio changes even if the primary pressure is lower than the secondary pressure, that is, the clutch pressure. Further, the cooling switching valve 50 has a structure shown in FIG.
As shown in (b), by having a relationship of D> d between the diameter D on the primary side and the diameter d on the clutch side, the primary pressure effectively acts on the diameter D of the spool valve 84 and becomes large. The pressure can be pressed to the right by the pressure, and in the diameter d on the clutch side, only the pressing force corresponding to the area ratio of the diameter D and the diameter d is generated. The spool valve 84 is moved leftward by the small pressing force due to the clutch pressure. It presses against. Therefore,
The spool valve 84 can be moved to the right in response to a slight change in the belt ratio, the sixth oil passage 48 and the oil cooling passage 60 are communicated with each other when the vehicle is running, and the oil flows into the oil cooler 56. , Oil cooling is performed.

As a result, the clutch can be cooled at the time of starting the vehicle, and the cooling switching valve can be switched to cool the oil while the vehicle is running, which can reduce pump loss of the oil pump and reduce the size of the oil pump. , Economically advantageous.

In addition, a spool valve having a simple structure is used as the cooling switching valve, and an area ratio between the diameter D on the primary side and the diameter d on the clutch side and a spring for urging the sixth oil passage and the oil cooling passage to communicate with each other are used. By setting, the optimum state can be easily realized, which is practically advantageous.

〔The invention's effect〕

As described above in detail, according to the present invention, in the belt drive type continuously variable transmission, the cooling passages for the clutch cooling and the oil cooling are provided, and the clutch cooling passage and the clutch cooling passage are provided in the middle of the cooling passage according to operating conditions. Since the switching valve for switching to the oil cooling passage is provided, the clutch cooling and the oil cooling can be switched depending on the operating condition, and the pump loss of the oil pump can be reduced. Further, the oil pump can be downsized, which is economically advantageous, and the configuration can be simplified, which is practically advantageous.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a schematic explanatory view of a cooling oil control device of a continuously variable transmission, and FIG. 2 (a) is a schematic sectional view showing a cooling switching valve at the time of starting. 2 (b) is a schematic cross-sectional view showing the cooling switching valve in the traveling state, and FIG. 3 is a view showing the relationship between the belt ratio and the oil flow according to the throttle diameter of the oil amount. In the figure, 2 is a belt drive type continuously variable transmission, 4 is a drive side pulley, 6 is a drive side fixed pulley part piece, 8 is a drive side movable pulley part piece, 10 is a driven side pulley, 12 is a driven side fixed A pulley piece, 14 is a driven side movable pulley piece, 16 is a rotating shaft,
18 is a first housing, 20 is a second housing, 22 is a first hydraulic chamber, 24 is a second hydraulic chamber, 26 is an urging means, 28 is an oil pump, 30 is a first oil passage, 32 is a second oil passage. , 34 is a primary pressure control valve, 36 is a pump pressure control valve, 38 is a third oil passage, 40 is a fourth oil passage, 42 is a constant pressure control valve, 44 is an oil pan, 46 is a fifth oil passage, and 48 is a fourth oil passage. 6 oil passages,
50 is a cooling switching valve, 52 is a hydraulic clutch, 54 is a clutch cooling passage, 56 is an oil cooler, 58 is an oil pan, 60 is an oil cooling passage, 62 and 64 are throttles, 66 is a primary pressure introduction passage,
68 is a clutch pressure control valve, 70 is a piston, 72 is a seventh oil passage, 74 is a clutch pressure introduction passage, 76 is a control unit, 78 is a pressure plate, 80 is a clutch disc, 82 is a body,
84 is a spool valve, 86 is an air hole, and 88 is a spring.

Claims (1)

[Claims] 1. Rotation of a belt wound around both pulleys by increasing / decreasing a width between both pulley parts of a fixed pulley part and a movable pulley part attached to the fixed pulley part so as to be able to come into contact with and separate from the fixed pulley part. In a belt-driven continuously variable transmission that changes the gear ratio by increasing or decreasing the radius, a cooling passage for clutch cooling and oil cooling is provided, and the clutch cooling passage and the oil cooling passage are provided in the middle of the cooling passage according to operating conditions. A cooling oil control device for a continuously variable transmission, characterized in that a switching valve for switching between the passage and the passage is provided.