JPH072660U - Continuously variable transmission - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to prevent overrun on the driven shaft side by mechanical control. [Structure] A fixed pulley piece fixed on a rotating shaft,
A driving pulley and a driven pulley, each of which has a movable pulley piece axially movably supported and which is transmitted through a belt; and a hydraulic oil chamber and a spring, which are provided in at least one of the pulleys. A stepless speed change step, in which the movable pulley pieces of the driving side pulley and the driven side pulley are moved in opposite directions by the hydraulic pressure of the hydraulic oil supplied to the hydraulic oil chamber to change the belt radii of the two pulleys to continuously change the speed. In the device, a pitot tube which is arranged on the driven pulley side and generates a pitot pressure by receiving an oil flow generated by the rotation of the driven pulley, and which is operated by the pitot pressure when the pitot pressure is a predetermined value or more. And a relief valve for reducing the hydraulic pressure in the hydraulic oil chamber.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a continuously variable transmission arranged between an engine and accessories in a vehicle, for example.

[0002]

[Prior art]

 As a conventional continuously variable transmission of this type, for example, there is one shown in FIG. 3 described in Japanese Patent Laid-Open No. 64-46056.

A fixed pulley piece 103 fixed to a crankshaft (drive shaft) 101 of an engine, a movable pulley piece 105 axially movably supported on the drive shaft 101, and a movable pulley piece 105 are fixed. A drive-side V-pulley 109 that includes a spring 107 that presses in the direction of the pulley piece 103, a fixed pulley piece 113 that is fixed to a rotating shaft (driven shaft) 111, and a movable shaft that is axially movably supported on the driven shaft 111. The driven-side V-pulley 119 including a pulley piece 115, an oil chamber 117 formed on the back side of the movable pulley piece 115, and a V-belt 121 wound between these V-pulleys 109 and 119 are provided. There is.

The oil chamber 117 of the driven V-pulley 119 is supplied with pressure oil whose discharge oil from the oil pump 123 is adjusted to a set pressure by the pressure control valve 125. The pressure control valve 125 is controlled by a control signal from the controller 127. The controller 127 inputs signals from the throttle sensor 129 that detects the load state of the engine, the rotation sensors 131 and 133 that detect the respective rotation speeds of the drive-side V pulley 109 and the driven-side V pulley 119, and outputs the signals from the engine. A control signal is output based on the control characteristic of the gear ratio between the driving V pulley 109 and the driven V pulley, which is set according to the load state.

Then, the hydraulic oil of the set pressure is supplied to the oil chamber 117 of the driven-side V pulley 119, so that the movable pulley piece 115 of the driven-side V pulley 119 approaches or separates from the fixed pulley piece 113. On the other hand, the movable pulley piece 105 of the drive-side V pulley 109 is moved by the spring 107 in the direction opposite to the moving direction of the movable pulley piece 115 of the driven pulley 119.

As a result, the ratio of the radii of rotation of the drive-side V pulley 109 and the driven-side V pulley 119 on which the V-belt 121 is applied is changed, and the gear ratio is changed.

[0007]

[Problems to be solved by the device]

 By the way, in such a continuously variable transmission arranged between the engine and the auxiliary machinery, if the shift range of the usage region is set to a region surrounded by a solid line in FIG. An overrun area surrounded by a chain line occurs.

When the driven shaft side for driving the auxiliary machine is driven at the rotational speed in this overrun region, the durability of the auxiliary machine is deteriorated due to the allowable amount of the compressor and the strength of other auxiliary machines. There was a problem that it could be damaged.

On the other hand, in the above-mentioned conventional continuously variable transmission, the gear ratio between the drive side V pulley 109 and the driven side V pulley 119 is controlled according to the load state of the engine, and further, Since the rotation speeds of the drive-side V pulley 109 and the driven-side V pulley 119 are detected by the rotation sensors 131 and 133, respectively, overrun prevention control can be easily performed.

However, the above-mentioned conventional device has a problem that the control becomes difficult when the electric signal is abnormal because the shift control is performed electrically.

Therefore, an object of the present invention is to provide a continuously variable transmission capable of preventing overrun on the driven shaft side by mechanical control.

[0012]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention has a fixed pulley piece fixed on a rotating shaft and a movable pulley piece axially supported so as to be movable in an axial direction. A driven pulley and a working oil chamber and a spring provided in at least one of the two pulleys are provided, and the movable pulley pieces of the driving and driven pulleys are moved by the hydraulic pressure of the working oil supplied to the working oil chamber. In a continuously variable transmission in which the pulleys are moved in opposite directions to change the belt radii of rotation of both pulleys and continuously variable speed is applied, an oil flow generated by the rotation of the driven pulley disposed on the driven pulley side is received. A pitot tube for generating pitot pressure and a relief valve for reducing the hydraulic pressure in the hydraulic oil chamber by the pitot pressure when the pitot pressure is a predetermined value or more are provided.

[0013]

[Action]

 By controlling the hydraulic pressure of the hydraulic oil supplied to the hydraulic oil chamber of one of the pulleys, the gear ratio between the driving pulley and the driven pulley is controlled.

When the rotation speed of the driven pulley exceeds a predetermined value and the Pitot pressure of the Pitot tube that receives the flow of oil generated by this rotation reaches a predetermined value or more, the relief valve operates due to this Pitot pressure, Reduce the hydraulic pressure in the hydraulic fluid chamber.

Therefore, it is possible to prevent the overrun of the driven shaft.

[0016]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of a continuously variable transmission according to an embodiment of the present invention. The continuously variable transmission 1 is a drive-side V pulley provided on a drive-side input shaft (drive shaft) 3. 5 and a driven-side V pulley 9 provided on a driven-side output shaft (driven shaft) 7, and is formed by winding a V-belt 11 between these pulleys 5 and 9.

The input shaft 3 is rotatably supported by the transmission case 13 via bearings 15 and 17, and the input shaft 3 is rotationally driven by a crankshaft (not shown) of an engine via a gear 19.

The drive-side V pulley 5 has a fixed pulley piece 21 fixed to the input shaft 3 and a movable pulley piece 23 rotatably supported on the input shaft 3 so as to be movable in the axial direction. A V groove 25 having a variable groove width is formed between the three.

A cylinder portion 27 is formed on the back surface of the movable pulley piece 23. Inside the cylinder portion 27, an outer edge portion of a guide member 29 whose base is fixed to the input shaft 3 is a seal member 31. It is fitted so as to be axially movable in a liquid-tight manner. Engaging teeth 33 are provided between the movable pulley piece 23 and the guide member 29.

In this way, the operating oil chamber 35 is formed by the input shaft 3, the movable pulley piece 23, and the guide member 29 on the back side of the movable pulley piece 23.

The working oil for moving the movable pulley piece 23 is supplied to the working oil chamber 35 from the oil pump 37 via the working oil pipe 41 and the working oil passage 43 through pressure control.

The hydraulic oil pipe 41 is connected to an oil introducing port 45 provided in the transmission case 13, a pressure control valve 39 is arranged in the middle of the hydraulic oil pipe 41, and a relief valve 47 is arranged downstream of the pressure control valve 39. Has been done. The leaf valve 47 is operated by the pitot pressure from a pitot pipe 49, which will be described later, and allows the pressure oil in the hydraulic oil chamber 35 to escape to the tank 51.

The working oil passage 43 is formed of an oil inlet 45, an oil passage 43 a, an oil outlet pipe 53, an oil passage 43 b, and a radial oil passage 43 c communicating with the working oil chamber 35. The oil outlet pipe 53 is relatively rotatably fitted into a support hole 55 formed in the shaft center of the input shaft 3 and communicates with the oil passage 43b.

The pressure control valve 39 can be manually operated from the driver's seat or can be automatically operated depending on the load condition of the engine.

On the other hand, the output shaft 7 is rotatably supported by the transmission case 13 via bearings 57 and 59, and a projection 61 for driving auxiliaries (not shown) is provided at a projecting portion on one end side thereof. Is fixed.

The driven-side V pulley 9 includes a fixed pulley piece 63 fixed to the output shaft 7, a movable pulley piece 65 axially movably supported on the output shaft 7, and the movable pulley piece 65 of the fixed pulley piece 63. A V-shaped groove 69 having a variable groove width is formed between the pulley pieces 63 and 65.

A Pitot tube 49 is arranged on the rear side of the fixed pulley piece 63 of the driven V pulley 9, and is fixed to the transmission case 13 by a bolt 71. Further, on the back surface of the fixed pulley piece 63, an annular straightening plate 73 for holding the flow of oil generated by the rotation of the driven V pulley 9 is attached.

The Pitot tube 49 receives a flow of oil generated by the rotation of the driven V pulley 9 to generate a Pitot pressure, and the Pitot tube 49 is connected to a relief valve via a conduit 75. There is. Then, the relief valve 47 operates by receiving the Pitot pressure generated in the Pitot tube 49 when the rotation speed of the driven V pulley 9 becomes equal to or higher than a predetermined value, and reduces the hydraulic pressure in the hydraulic oil chamber 35. ing.

Next, the operation of the above-described embodiment will be described.

The driving force of the engine is transmitted to the driving side V pulley 5 via the input shaft 3, and is transmitted to the output shaft 7 via the V belt 11 and the driven side V pulley 9.

When the pressure control valve 39 is controlled by, for example, manual operation, the hydraulic oil from the oil pump 37 is adjusted to the set hydraulic pressure by the pressure control valve 39, and passes through the conduit 41 and the oil passage 43 to drive the V pulley 5 on the drive side. Is supplied to the hydraulic oil chamber 35. Due to this hydraulic pressure, the movable pulley piece 23 moves toward or away from the fixed pulley piece 21, while the movable pulley 65 of the driven V pulley 9 is moved by the spring 67 to move the driving V pulley 5. The pulley piece 23 moves in a direction opposite to the moving direction.

As a result, the ratio of the radii of rotation of the V-belt 11 that is wound around the drive-side V pulley 5 and the driven-side V pulley 9 is changed, and the gear ratio is changed.

In this way, the rotation speed of the driven-side V pulley 9 that is gear-shifted becomes equal to or higher than a predetermined value, and the pitot pressure of the pitot tube 49 that receives the oil flow generated by the rotation of the driven-side V pulley 9 is set to a predetermined value. When the pressure exceeds the value, this Pitot pressure acts on the relief valve 47 via the conduit 75, and the relief valve 47 operates to allow the hydraulic oil in the hydraulic oil chamber 35 to escape to the tank 51 so that the hydraulic pressure in the hydraulic oil chamber 35 increases. Lower.

As a result, the movable pulley piece 23 of the drive-side V pulley 5 moves in the direction away from the fixed pulley piece 21, while the movable pulley piece 65 of the driven-side V pulley 9 approaches the fixed pulley piece 63. By moving, the gear ratio between the driving V pulley 5 and the driven V pulley 9 becomes smaller.

Therefore, the overrun of the driven shaft 7 can be prevented with a simple mechanical structure, and the durability and the damage of the auxiliary machinery can be prevented.

[0037]

[Effect of device]

 As is clear from the above description, according to the configuration of the present invention, the overrun on the driven side can be prevented by the mechanical control, and thus the durability and the damage of the auxiliary machinery can be prevented. You can

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing an example of setting a use area in a continuously variable transmission.

FIG. 3 is a configuration diagram of a conventional example.

[Explanation of symbols]

 1 continuously variable transmission 3 input shaft (drive shaft) 5 drive side V pulley 7 output shaft (driven shaft) 9 driven side V pulley 11 V belt 21 fixed pulley piece 23 movable pulley piece 35 hydraulic oil chamber 47 relief valve 49 pitot tube 63 Fixed pulley piece 65 Movable pulley piece 67 Spring

Claims (1)

[Scope of utility model registration request] 1. A drive-side pulley and a driven-side pulley, each of which has a fixed pulley piece fixed on a rotating shaft and a movable pulley piece axially movably supported, and which is transmitted via a belt. Equipped with a hydraulic oil chamber and a spring provided in at least one of the two pulleys, the movable pulley pieces of the drive side and driven side pulleys are moved in opposite directions by the hydraulic pressure of the hydraulic oil supplied to the hydraulic oil chamber. In a continuously variable transmission that changes the belt radii of rotation of both pulleys to perform continuously variable transmission, a Pitot tube that is arranged on the driven pulley side and receives a flow of oil generated by the rotation of the driven pulley to generate Pitot pressure And a relief valve that is operated by the pitot pressure to reduce the hydraulic pressure in the hydraulic oil chamber when the pitot pressure is equal to or higher than a predetermined value.