KR20150026474A - Transmission apparatus of vehicle and controlling method thereof - Google Patents

Abstract

According to the present invention, a transmission for a vehicle comprises: a hydrostatic transmission (HST) part receiving power from an engine; a planetary gear part having multiple planetary gears to synthesize the power transmitted from the engine continuously by the HST and the power not transmitted from the engine by the HST; an auxiliary transmission part transmitting a rotation driving force from the planetary gear part to a first driven shaft selectively; a malfunction determination unit to determine the malfunction of the HST; and a power switch unit switching the power from the engine to be directly transmitted from the planetary gear part to the auxiliary transmission part without being passed through the HST when the malfunction of the HST is determined by the malfunction determination part. According to the present invention, even if the HST or the electronic control unit thereof malfunctions while a tractor is stopped or driven, the transmission of the power from the engine can be controlled to prevent inability to start or control the tractor, thereby improving driving stability.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a transmission for a vehicle,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission of a vehicle and a control method thereof, and more particularly to a continuously variable transmission suitable for a working vehicle such as a tractor and a control method thereof.

BACKGROUND ART As a power transmission system for a work vehicle such as a tractor, a hydraulic mechanical transmission (HMT) in which a hydraulic type continuously variable transmission (HST) and a mechanical differential device are combined is used.

Hydraulic mechanical transmissions are transmissions that maximize the benefits of both a hydraulic continuously variable transmission with excellent operability and a differential gear with excellent transmission efficiency.

Further, in the case of a hydraulic mechanical transmission used in a conventional working vehicle, it is general to use a multi-speed transmission having two or more power transmission paths using one or more planetary gears and a continuously variable transmission. In this case, the output of the engine continuously variable by the hydraulic type continuously variable transmission and the output of the engine that is not shifted by the continuously variable transmission are combined using the planetary gear, and the synthesized power is selectively transmitted to the axle using the clutch .

In such a conventional hydraulic mechanical transmission, the power of the engine, which is continuously variable by the hydraulic type continuously variable transmission, is transmitted to one of the plurality of rotary elements of the plurality of planetary gears, Is transmitted to any one of the other rotary elements except for the rotary element.

Therefore, when an abnormality occurs in the hydraulic circuit in the hydraulic control type continuously variable transmission, or when an abnormality occurs in the electronic control device for controlling the hydraulic type continuously variable transmission, and the output shaft of the hydraulic type continuously variable transmission idles, So that the hydraulic mechanical transmission is no longer able to control the transmission of the output of the engine to the axle.

In particular, when such a hydraulic type continuously variable transmission fails during driving or during operation of the tractor, it can not oscillate from the stopped state, and the tractor can be moved to the place for maintenance without separate towing equipment or the tractor There is a problem that it can not be done.

Korean Patent Laid-Open Publication No. 10-2012-0086822

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to provide a vehicular automatic transmission that can control power transmission of an engine even when a hydraulic type continuously variable transmission or its electronic control device fails during stopping or running of the tractor, Thereby improving the running stability of the vehicle.

In order to achieve the above object, according to the present invention, the power of an engine that is continuously-variable-shifted by a hydraulic type continuously variable transmission portion into which a power from an engine is input and the power of an engine that is not shifted by a hydraulic type- Characterized in that the transmission includes a planetary gear portion synthesized by the planetary gear of the planetary gear set of the automatic transmission portion and a negative speed change portion selectively transmitting the rotational driving force from the planetary gear portion to the first driven shaft, ; And a power switching means for switching the power from the engine to be directly transmitted from the planetary gear portion to the auxiliary speed change portion without passing through the hydraulic type stepless speed change portion when a failure of the hydraulic type stepless speed change portion is determined by the failure determination means And power switching means for switching the power from the provided engine to be directly transmitted from the planetary gear portion to the auxiliary speed change portion.

Preferably, the input shaft of the hydraulic power stepless transmission portion of the present invention is connected to the drive input shaft of the engine, and the output shaft of the hydraulic stepless transmission portion is connected to the first rotary element of the plurality of planetary gears of the planetary gear portion.

Preferably, the power switching means of the present invention is a brake provided so as to fix the first rotary element.

Preferably, the power switching means of the present invention is a clutch for switching the power between the input shaft and the drive input shaft of the hydraulic type stepless transmission.

Preferably, the power switching means of the present invention is a clutch for switching the power between the input shaft of the brake and the hydraulic stepless speed change section and the drive input shaft of the engine, the brake being provided to fix the first rotating element.

Preferably, the planetary gear portion of the present invention is constituted so that the planetary gear portion of the present invention includes a carrier and a sun gear shaft which are respectively rotated by a combined drive force of a power of an engine which is continuously variable by the hydraulic stepless speed change portion, And the auxiliary speed change section includes a first speed change section that receives power from the carrier and transmits the power to the first driven shaft; And a second transmission portion that receives power from the sun gear shaft and outputs the power to the first driven shaft, wherein the first speed change portion or the second speed change portion is selectively connected to the first driven shaft at the time of shifting.

Preferably, the sun shaft of the present invention is connected freely rotatably on a drive input shaft, and the carrier is connected freely rotatably on a sun shaft.

Preferably, the present invention provides a steering apparatus comprising: a first sun gear fixed to a drive input shaft; A second sun gear formed on the sun shaft; A ring gear rotatably rotatable about a driving input shaft and installed to surround the second sun gear; And a plurality of planetary gears having a first pinion gear connected to the first sun gear and a second pinion gear connected to the ring output gears of the second sun gear and the ring gear at the same time, And is fastened.

Preferably, the first rotary element is a ring gear.

Preferably, the vehicle is a working vehicle and the driving input shaft is connected to a working device of the working vehicle.

In order to achieve the above object, according to the present invention, the power of an engine that is continuously-variable-shifted by a hydraulic type continuously variable transmission portion into which a power from an engine is input and the power of an engine that is not shifted by a hydraulic type- And a transmission portion selectively transmitting the rotational driving force from the planetary gear portion and the planetary gear portion synthesized by the planetary gear of the planetary gear unit to the first driven shaft, comprising: determining whether the hydraulic type of the stepless transmission is in a failure state; And a step of switching the transmission of power from the hydraulic type stepless speed change section to the hydraulic type stepless speed change section by fixing the rotation element of the planetary gear of the planetary gear section connected to the hydraulic type stepless speed change section when it is judged that a failure has occurred in the hydraulic type stepless transmission section Control method.

Preferably, the step of switching the power from the hydraulic power stepless transmission portion of the present invention is characterized in that the rotary element is fixed so as not to be rotatable by using a brake connected to the rotary element.

Preferably, the step of switching the power from the hydraulic power stepless transmission portion of the present invention is used for a clutch that selectively connects the hydraulic power stepless transmission portion and the engine, thereby releasing the connection between the hydraulic stepless transmission portion and the engine .

Preferably, the step of switching the power from the hydraulic power stepless transmission portion of the present invention is used for a clutch that selectively connects the hydraulic power stepless transmission portion and the engine, thereby releasing the connection between the hydraulic stepless transmission portion and the engine In addition, the rotary element is fixed so as not to be rotatable by using a brake connected to the rotary element.

Preferably, the step of switching the power from the hydraulic power stepless transmission portion of the present invention further includes the step of controlling the speed change stage of the auxiliary speed change portion.

According to the present invention, it is possible to transmit and control the power from the engine to the axle via the mechanical transmission means even when the hydraulic type CVT or its electronic control device fails during the stop or stop of the tractor, And the running stability of the working vehicle can be improved.

1 is a block diagram showing a power transmission relationship of a transmission according to the present invention;
2 is a diagram showing the configuration of the transmission according to the present invention.
3 is a diagram showing a transmission configuration according to another embodiment of the present invention.
4 is a diagram showing a transmission configuration according to another embodiment of the present invention.
5 is a flowchart of an embodiment of a method of controlling a transmission according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Although the present invention has been described with reference to the embodiments shown in the drawings, it is to be understood that the present invention is not limited thereto.

1 is a block diagram showing a power transmission relationship between a hydraulic type stepless transmission portion of the present invention and a transmission 1 using a planetary gear portion.

As shown, the transmission 1 according to the present invention includes a hydraulic stepless change-speed section 4, a planetary gear section 3, and an auxiliary speed change section 5.

In the transmission 1 according to the present invention, the engine 2 and the planetary gear portion 3 are connected via two power transmission paths. The first power transmission path is a pure mechanical path without using a hydraulic power transmission element, and the second power transmission path is a hydraulic path via a hydraulic type stepless change transmission portion 4 which is shifted using hydraulic pressure. Here, the hydraulic path means that the fluid is used for the power conversion and does not mean that the power transmission is made solely of fluid.

In the first power transmission path, which is a mechanical path, the engine power is directly transmitted to the planetary gear portion 3 without shifting action. In the second power transmission path, which is a hydraulic path, the driving force of the engine 4 is transmitted to the hydraulic type stepless transmission portion 4, And is transmitted to the planetary gear portion 3.

In the planetary gear portion 3, the driving force of the engine 2 transmitted by the first power transmission path and the driving force of the continuously-variable shifting engine 2 transmitted by the second power transmission path are combined to form the auxiliary transmission portion 5 . The planetary gear portion 3 is composed of two or more planetary gears, and each planetary gear is composed of a plurality of rotation elements. The power transmitted from the engine 2 by the first power transmission path and the second power transmission path is transmitted to any one of the plurality of different rotation elements.

The auxiliary transmission portion 5 has two or more speed stages and has a plurality of input stages for this purpose. For example, when the auxiliary speed change section 5 is selected as low speed, power is received from a low speed input end, and when the high speed end is selected, power is delivered to a high speed input end.

The planetary gear unit 3 is provided with a plurality of output stages connected to a plurality of rotary elements and each output end of the planetary gear unit 3 is selectively connected to a plurality of input stages of the negative speed change portion 5. Speed input end of the auxiliary transmission portion 5 is connected to the low speed output end of the planetary gear portion 3 and the high speed input end of the auxiliary speed change portion 5 is connected to the high speed output end of the planetary gear portion 3, Two inputs are not connected at the same time and only one input is connected.

According to the embodiment of the present invention, the transmission according to the present invention is configured such that an abnormality occurs in the hydraulic control circuit for controlling the hydraulic circuit or the hydraulic stepless speed change section 4 in the hydraulic stepless speed change section 4, (9) for judging the occurrence of a failure.

When a failure occurs in the hydraulic power stepless speed change section 4, the power output from the engine 2 may not be properly controlled by the hydraulic power stepless transmission section 4, or the power transmission itself may be disabled . In this case, the running control of the vehicle may not be properly performed. In particular, when the output end of the hydraulic type stepless change-speed section 4 idles, the rotational element of the planetary gear portion 3 connected to the hydraulic type stepless change-speed portion 4 is not fixed, It becomes a neutral state. In this case, the power of the engine 2 can not be transmitted to the negative speed change portion 3 through the planetary gear portion 3, and the running vehicle can be stopped or can not be started in a stopped state.

Therefore, according to the embodiment of the present invention, the transmission according to the present invention cuts off the second power transmission path, and the power of the engine 2 transmitted by the first power transmission path, which is a mechanical path, And power transmission means (8) for transmitting the power to the vehicle.

The power switching means 8 according to the preferred embodiment of the present invention shown in Fig. 2 is a brake 130 for fixing a rotating element of the planetary gear portion 3 connected to the hydraulic stepless speed change portion 4.

In the transmission 1 according to the present invention, when the failure determination means 9 determines that a failure has occurred in the hydraulic power stepless speed change section 4, the brake 130 is operated so that the hydraulic stepless speed change section 4 The rotation of the rotary element of the connected planetary gear unit 3 is stopped to fix the rotary element. By stopping the rotation of the rotary element of the planetary gear portion 3 connected to the hydraulic type stepless speed change portion 4 while cutting off the transmission of the power in the hydraulic type stepless transmission portion 4, To be in a neutral state.

The power switching means 8 according to the preferred embodiment of the present invention shown in Fig. 3 is a clutch 140 selectively connecting the hydraulic stepless speed change section 4 and the engine 2. As shown in Fig.

In the transmission 1 according to the present invention, when the failure determination means 9 determines that a failure has occurred in the hydraulic power stepless speed change section 4, the clutch 140 is operated, and the hydraulic stepless change- And releases the connection between the first and second portions 4a and 4b. In this case, no power is transmitted from the engine 2 to the hydraulic type stepless speed change section 4, and the output shaft of the hydraulic type stepless transmission section 4 is maintained in a fixed state without rotating. Thus, while the power transmission in the hydraulic type stepless change-speed section 4 is interrupted, the rotary element of the planetary gear part 3 connected to the hydraulic type stepless change-speed section 4 is fixed and the planetary gear part 3 is in the neutral state Thereby preventing it from falling out.

In the transmission 1 shown in Fig. 4, the power switching means 8 according to the preferred embodiment of the present invention includes a brake (not shown) for fixing the rotating element of the planetary gear portion 3 connected to the hydraulic stepless speed change portion 4 130 and the clutch 140 selectively connecting the hydraulic stepless speed change section 4 and the engine 2. [

In the transmission 1 according to the present invention, when the failure determination means 9 determines that a failure has occurred in the hydraulic type stepless speed change section 4, the clutch 140 is disengaged and the power of the engine 2 is released And the rotation of the planetary gear portion 3 connected to the hydraulic type stepless speed change portion 4 is fixed by the brake 130 so that the power is cut off more reliably . Thereby, the power from the engine 2 is transmitted to the negative speed change portion 5 via the planetary gear portion 3 by the mechanical power transmission means.

2 to 4 are diagrams schematically showing the structure of the transmission 1 according to the present invention in the case where the brake 130 and the clutch 140 are provided only as the power switching means 8, The structure of the transmission 1 according to the present invention will be mainly described with reference to Fig. 2, and a repeated description of Fig. 3 and Fig. 4 will be omitted.

2, the transmission 1 according to the embodiment of the present invention includes a drive input shaft 10 connected to an output portion of the engine 2 and rotated by the power of the engine 2, A hydraulic type continuously variable transmission portion 4 for transmitting the combined driving force to the planetary gear portion 3 by receiving the driving force from the driving input shaft 10, a planetary gear portion 3 formed about the planetary gear portion 10, 3 includes a secondary transmission portion 5 for receiving power from the vehicle, a forward / backward switching portion 6 for switching forward and backward movement of the vehicle, and a secondary planetary gear portion 7 formed to reduce the clutch capacity of the transmission do.

A first sun gear 11 is fixed to the most upstream side of the drive input shaft 10 and an HST input drive gear 18 is fixed to the middle of the downstream side. A working device driving shaft 110 for driving a working device of the working vehicle is connected to the most downstream side of the driving input shaft 10 via a clutch 111. The work device in which the work device drive shaft 110 is connected to the drive input shaft 10 through the clutch 111 can be moved up and down.

As used herein, the term " upstream "means a side to which power is input by one member, and the term" downstream " means a side to which power input from the member is transmitted.

The HST input drive gear 18 is connected to the HST input driven gear 45 fixed on the HST input shaft 43 for inputting power to the HST unit 40 of the HST unit 40. [ In this embodiment, the HST input drive gear 18 is connected to the HST input driven gear 45 through the connecting gear 19. [

The HST unit 40 includes a hydraulic pump 41 and a hydraulic motor 42. The rotational force of the drive input shaft 10 driven by the engine 2 is transmitted to the HST input shaft 43 through the gears 18, 19 and 43. The hydraulic pump 41 is driven by the driving force of the HST input shaft 43 .

The hydraulic pump 41 is configured to adjust the inclination angle of the swash plate provided therein to variably adjust the capacity of the internal flow rate. The hydraulic pump 41 drives the hydraulic motor 42.

The HST unit 40 can adjust the driving ratio of the hydraulic motor 42 to the hydraulic pump 41 by adjusting the capacity of the hydraulic pump 41 and thereby adjust the magnitude of the output power. The hydraulic motor 42 rotates the HST output shaft 44 of the HST unit 40.

Since the structure of the hydraulic type continuously variable transmission that receives the driving force of the engine 2 and decelerates the driving force of the engine 2 like the HST unit 40 is well known in the art, a more detailed description of the structure and power transmission characteristics of the HST unit 40 is omitted here do.

On the other hand, on the downstream side of the first sun gear 11 of the drive input shaft 10, there are provided a sun gear shaft 30 which is freely rotatable on the drive input shaft 10, a carrier which is freely rotatable on the sun shaft 30, a carrier 20 is provided. And a second sun gear 31 is provided at the upstream end of the sun shaft 30.

A plurality of planetary gears (12) are connected to the first sun gear (18) and the second sun gear (31). The plurality of planetary gears 12 includes a first pinion gear 13 connected to the first sun gear 18 and a second pinion gear 14 connected to the second sun gear 31.

As shown in Fig. 2, the carrier 20 is fastened to the plurality of planetary gears 12 at the same time.

A ring gear 15 is installed to enclose the second sun gear 31 in order to combine the driving force of the HST unit 40 and the rotational driving force of the driving input shaft 10 according to the present embodiment.

The ring output gear 17 of the ring gear 15 is connected to the second pinion gear 14 of the planetary gear 12 and the ring input gear 16 is connected to the HST output shaft 44 of the HST unit 40 And is connected to the HST output drive gear 46.

The ring gear 15 is freely rotatable with respect to the drive input shaft 10 by rotational drive of the HST output shaft 44. [

On the other hand, according to the embodiment of the present invention, the ring gear 15 is connected to the brake 130 which fixes the ring gear 15 to be unable to rotate. When the brake 130 determines that a failure has occurred in the hydraulic circuit or the electric control device of the hydraulic type stepless speed change section 4 by the failure determination means 9 shown in Fig. 1, the brake 130 does not rotate the ring gear 15 Fixed.

When the engine 2 is driven, the driving input shaft 10 is rotated, and the rotational driving force 10 of the driving input shaft 10 rotates the HST input shaft 43. The rotational driving force of the HST input shaft 43 is input to the HST unit 40 and the HST unit 40 outputs the HST output

Thereby rotating the shaft 44.

When the HST output shaft 44 rotates, the ring gear 15 connected to the HST output drive gear 46 rotates about the drive input shaft 10.

On the other hand, when the driving input shaft 10 is rotated by the driving force of the engine 2, the first sun gear 11 fixed to the driving input shaft 10 also rotates.

A plurality of planetary gears 12 connected to the first sun gear 11 and the ring gear 15 are connected to the first sun gear 11 and the ring gear 15, respectively, as the first sun gear 11 and the ring gear 15 rotate, (15) in the vicinity of the drive input shaft (10).

At this time, since the revolution speeds of the planetary gears 12 are all the same, the carrier 20, which is simultaneously engaged with the planetary gears 12, rotates around the driving input shaft 10.

The sun gear shaft 30 connected to the second pinion gear 14 of the planetary gear 12 is rotated by the rotation of the planetary gear 12, And is rotated about the driven input shaft 10 by the motion and the idle motion.

That is, according to the present embodiment, the rotational driving force of the driving input shaft 10 directly driven by the engine 2 and the rotational driving force of the HST output shaft 94 driven by the HST unit 90 are transmitted to the planetary gear 12 And the combined driving force rotates the carrier 20 and the sun shaft 30, respectively.

On the other hand, according to the present embodiment, when it is judged by the failure judging means 9 shown in Fig. 1 that a failure has occurred in the hydraulic circuit or the electric control device of the hydraulic type stepless speed change section 4, the ring gear 15 Fix it not to rotate. Therefore, when the driving input shaft 10 is rotated by the driving force of the engine 2, the first sun gear 11 fixed to the driving input shaft 10 also rotates. A plurality of planetary gears 12 connected simultaneously to the first sun gear 11 and the ring gear 15 are connected to the first sun gear 11 and the second sun gear 11 via the first sun gear 11 and the ring gear 15, 11 and the ring gear 15 so as to revolve around the drive input shaft 10.

At this time, since the revolution speeds of the planetary gears 12 are all the same, the carrier 20, which is simultaneously engaged with the planetary gears 12, rotates around the driving input shaft 10. Therefore, even if a failure occurs in the hydraulic stepless speed change section 4 and the clutch can not be controlled, the drive force from the engine 2 is transmitted to the auxiliary speed change section in accordance with the power transmission path input from the first sun gear 11, It is possible to deliver.

According to the present embodiment, the auxiliary transmission portion 5 that performs the shifting operation by receiving the rotational force of the carrier 20 and the sun shaft 30 is provided.

Specifically, as shown in FIG. 2, the carrier 20 is provided with a 1/3 stage drive gear 21 connected to the 1/3 speed change portion.

The 1/3 speed shifting portion includes a 1/3 speed driven gear 59 connected to the 1/3 speed drive gear 21 and a 1/3 speed drive shaft 57 having the first clutch 51, A three-stage drive gear 61 that is freely rotatable on the 1/3 stage drive shaft 57 and is connected to the first clutch portion 53 and the second clutch portion 54 of the first clutch 51, And a first-stage drive gear 62.

On the other hand, the sun gear shaft 30 is formed with a 2/4 step drive gear 32 connected to the 2/4 step transmission portion.

The 2/4-speed transmission portion includes a 2/4-speed driven gear 60 connected to the 2/4-speed drive gear 32, a 2/4-speed drive shaft 58 having the second clutch 52, A four-stage drive gear 63 which is freely rotatable on the 2/4 stage drive shaft 58 and is connected to the third clutch portion 55 and the fourth clutch portion 56 of the second clutch 52, And a two-stage drive gear 64.

The 1/3 speed shifting portion and the 2/4 speed shifting portion are connected to the first driven shaft 70. The first driven shaft 70 includes a 3/4 driven gear 71 connected to the 3-stage drive gear 61 and the 4-stage drive gear 63 at the same time, Stage driven gear 72 which is simultaneously connected to the first-stage driven gear 64 is formed.

The first driven shaft (70) extends to the forward / backward switching portion (6). The third clutch 80 having the fifth clutch portion 81 and the sixth clutch portion 82 is formed in the forward-reverse switching portion 6, and the third driven shaft 100 is rotated freely A forward / backward output gear 91 is fixed.

The second driven shaft 90 is rotatably supported with respect to the second driven shaft 90 and is rotatably supported by a reverse drive gear (not shown) which can be selectively connected to the fifth clutch portion 81 and the sixth clutch portion 82 83 and a forward driving gear 84 are formed.

A reverse connection gear 73 connected to the reverse drive gear 83 via the reverse idle gear 85 and a forward connection gear 74 connected to the forward drive gear 84 are formed in the first driven shaft 70 So that power can be transmitted from the auxiliary transmission portion 5 to the forward / backward switching portion 6.

The third driven shaft 100 which is freely rotatable with respect to the forward and backward output gear 91 of the second driven shaft 90 is connected to the wheel 120 of the vehicle and is driven by the rotational driving force of the third driven shaft 100 The wheels of the vehicle are driven.

The connection shaft 101 is provided in parallel with the third driven shaft 100 to reduce the clutch capacity of the auxiliary transmission portion 5 and the forward / backward switching portion 6, A portion 7 is formed.

The connection shaft 101 is provided with a first reduction gear 102 connected to the forward and reverse output gear 91 and a second reduction gear 102 connected to the third driven shaft driven gear 104 fixed to the third driven shaft 100. [ A gear 103 is formed.

Since the third driven shaft 100 is rotatably connected to the forward / backward output gear 91 in a freely rotatable manner, the rotational force of the second driven shaft 90 is directly transmitted to the third driven shaft 100 The second deceleration of the power is achieved.

3 is a diagram schematically showing a transmission according to another preferred embodiment of the present invention. The transmission shown in Fig. 3 is provided with a clutch 130 on the HST input shaft 43 between the HST unit 40 and the HST input driven gear 45 in place of the brake 130 connected to the ring gear 15, (140) is provided.

On the other hand, according to the present embodiment, when it is judged by the failure judging means 9 shown in Fig. 1 that a failure has occurred in the hydraulic circuit or the electric control device of the hydraulic type stepless speed change section 4, The connection between the unit 40 and the HST input driven gear 45 is released.

In this case, the driving force transmitted from the engine 2 is not transmitted to the HST unit 40, and therefore, the output shaft 46 of the HST unit 40 is fixed irrotationally. Therefore, the ring gear 15 of the planetary gear portion 3 connected to the HST output shaft 46 is also not rotatably fixed via the HST output drive gear 46.

Therefore, when the driving input shaft 10 is rotated by the driving force of the engine 2, the first sun gear 11 fixed to the driving input shaft 10 also rotates. A plurality of planetary gears 12 connected simultaneously to the first sun gear 11 and the ring gear 15 are connected to the first sun gear 11 and the second sun gear 11 via the first sun gear 11 and the ring gear 15, 11 and the ring gear 15 so as to revolve around the drive input shaft 10.

At this time, since the revolution speeds of the planetary gears 12 are all the same, the carrier 20, which is simultaneously engaged with the planetary gears 12, rotates around the driving input shaft 10. Therefore, even if a failure occurs in the hydraulic stepless speed change section 4 and the clutch can not be controlled, the drive force from the engine 2 is transmitted to the auxiliary speed change section in accordance with the power transmission path input from the first sun gear 11, It is possible to deliver.

4 is a diagram schematically showing a transmission according to another preferred embodiment of the present invention. The transmission shown in Figure 4 has a brake 130 connected to the ring gear 15 and an HST input shaft 43 between the HST unit 40 and the HST input driven gear 45, And that a clutch 140 is provided together with the clutch 140.

On the other hand, according to the present embodiment, when it is judged by the failure judging means 9 shown in Fig. 1 that a failure has occurred in the hydraulic circuit or the electric control device of the hydraulic type stepless speed change section 4, In addition to releasing the connection between the unit 40 and the HST input driven gear 45, the brake 130 fixes the ring gear 15 so as not to rotate.

This prevents the driving force transmitted from the engine 2 from being transmitted to the HST unit 40 and allows the planetary gear portion 3 to rotate freely while fixing the ring gear 15 of the planetary gear portion 3 Thereby preventing it from falling into a neutral state. According to the embodiment shown in Fig. 4, it is possible to reliably prevent the planetary gear portion 3 from being put in the neutral state, in addition to being able to prevent the increase in load on the output of the engine 2.

5 shows a flowchart of an embodiment of a method of controlling a transmission according to the invention.

First, the failure occurrence determining means (9) determines the failure of the hydraulic type stepless speed change section (3). The failure occurrence determining means 9 determines whether or not the hydraulic type stepless speed change section 3 is faulty by checking whether there is an abnormality in the hydraulic circuit in the hydraulic type stepless transmission portion 3 or in a control device for electrically controlling the hydraulic circuit. .

When the failure occurrence determining means 9 determines that a failure has occurred in the hydraulic power stepless speed change section 3, the transmission of power from the hydraulic power stepless speed change section 3 is switched so that the hydraulic power transmission path, And the power of the engine 1 is transmitted through the planetary gear portion 3 to the auxiliary speed change portion 5 through the first power transmission path which is the mechanical power transmission path.

5, the step of switching the power from the hydraulic power stepless speed change section 3 includes switching the power to the input section of the HST unit 40 (step S20) and the step of switching the power from the planetary gear section 3 (Step S30) of operating the brake provided at the output terminal of the HST unit 40 connected to the rotation element of the HST unit 40. [ The clutch 140 provided between the engine 2 and the input unit of the HST unit 40 is released to interrupt the transmission of power from the engine 2 to the HST unit 40. [ The rotary element of the planetary gear portion 30 and the brake provided at the output end of the HST unit 40 are actuated to fix the rotation element of the planetary gear portion 30 connected to the HST unit 40 in a rotatable manner.

According to the preferred embodiment shown in FIG. 5, the power switching to the input portion of the HST unit 40 is switched (S20) and the brake (S30) provided at the output terminal of the HST unit is operated Depending on the failure state of the continuously-variable transmission portion 40, only one of the above two steps may be performed.

According to a preferred embodiment of the present invention, the transmission control method of the present invention further includes a step S40 of controlling the speed change stage of the auxiliary speed change section 5. [ When a failure occurs in the hydraulic stepless speed change section 4, it is necessary to appropriately control the traveling state of the vehicle so as to move the vehicle to a predetermined position. Therefore, in the present invention, the speed change stage of the auxiliary speed change section 5 is controlled to control the output from the engine 2 so that the running control of the vehicle by the driver can be properly performed.

1: Transmission
2: engine
3: planetary gear portion
4: HST unit section
5:
6: forward /
7: 2nd deceleration section
8: Power switching means
10: drive input shaft
11: 1st sun gear
12: Planetary gear
15: Ring gear
20: Carrier
30: Sun shaft
31: 2nd sun gear
51, 52, 80, 140: clutch
70: first driven shaft
90: second driven shaft
100: Third driven shaft
130: Brake

Claims (15)

A power transmitting mechanism for transmitting the power of an engine continuously-variable-shifted by the hydraulic power stepless transmission portion and the power of an engine which is not shifted by the hydraulic stepless transmission portion by a plurality of planetary gears And a transmission portion for selectively transmitting a rotational driving force from the planetary gear portion to the first driven shaft,
A failure determining means for determining a failure of the hydraulic control unit; And
And power switching means for switching the power from the engine to be directly transmitted from the planetary gear portion to the auxiliary speed change portion without passing through the hydraulic type stepless speed change portion when a failure of the hydraulic type stepless speed change portion is determined by the failure determination means And wherein the transmission mechanism is a transmission mechanism. The method according to claim 1,
The input shaft of the hydraulic power stepless transmission is connected to the drive input shaft of the engine,
And the output shaft of the hydraulic stepless change-speed section is connected to a first rotary element of a plurality of planetary gears of the planetary gear section. The method of claim 2,
And the power switching means is a brake provided so as to be able to fix the first rotary element in a non-rotatable manner. The method of claim 2,
Wherein the power switching means is a clutch for switching the power between the input shaft of the hydraulic power stepless transmission portion and the drive input shaft. The method of claim 2,
Wherein the power switching means comprises:
A brake provided so as to rotatably fix the first rotary element, and
And a clutch for switching power between an input shaft of the hydraulic power stepless transmission portion and a drive input shaft of the engine. The method of claim 2,
The planetary gear unit
And a carrier and a sun gear shaft which are respectively rotated by a combined driving force of a power of an engine which is continuously variable by the hydraulic stepless speed change section and an engine which is not shifted by the hydraulic stepless speed change section,
Wherein the auxiliary speed-
A first transmission portion that receives power from the carrier and transmits the power to the first driven shaft; And
And a second transmission portion that receives power from the sunk shaft and outputs the power to the first driven shaft,
Wherein the first speed change portion or the second speed change portion is selectively connected to the first driven shaft at the time of shifting. The method of claim 6,
Wherein the sun gear shaft is freely rotatably connected to the drive input shaft, and the carrier is freely rotatably connected to the sun gear shaft. The method of claim 7,
A first sun gear fixed to the drive input shaft;
A second sun gear formed on the sun shaft;
A ring gear rotatable about the driving input shaft and installed to surround the second sun gear;
Further comprising a plurality of planetary gears including a first pinion gear connected to the first sun gear and a second pinion gear connected to the ring gears of the ring gears of the ring gear and the second sun gear,
And the carrier is simultaneously engaged with the plurality of planetary gears. The method of claim 8,
And the first rotary element is the ring gear. The method of claim 6,
The vehicle is a working vehicle,
And the drive input shaft is connected to a working device of the working vehicle. A power transmitting mechanism for transmitting the power of the engine continuously variable by the hydraulic stepless speed change section to the power of the engine which is not shifted by the hydraulic stepless speed change section by a plurality of planetary gears, A transmission for a vehicle, comprising: a gear portion; and a negative speed change portion that selectively transmits a rotational driving force from the planetary gear portion to a first driven shaft,
Determining whether the hydraulic stepless speed change section has failed;
And switching the transmission of power from the hydraulic type stepless speed change section to the hydraulic type stepless speed change section by fixing a rotary element of the planetary gear of the planetary gear section connected to the hydraulic type stepless speed change section when it is judged that a failure has occurred in the hydraulic type stepless speed change section And a control method of the vehicle transmission. The method of claim 11,
Wherein the step of switching the power from the hydraulic stepless change-speed section is performed by using a brake connected to the rotary element so that the rotary element is fixed so as not to be rotatable. The method of claim 11,
Characterized in that the step of switching the power from the hydraulic power stepless transmission portion is used for a clutch that selectively connects the hydraulic power stepless transmission portion and the engine so as to release the connection between the hydraulic power stepless transmission portion and the engine A method of controlling a transmission for a vehicle. The method of claim 11,
Wherein the step of switching the power from the hydraulic power stepless speed change section is used for a clutch that selectively connects the hydraulic power stepless transmission section and the engine to release the connection between the hydraulic power stepless transmission section and the engine, Wherein the rotation element is fixed so as not to be rotatable by using a brake connected to the rotation element. The method of claim 11,
Wherein the step of switching the power from the hydraulic stepless speed change section further comprises a step of controlling a speed change stage of the auxiliary speed change section.

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