JPH0625573B2 - Gear transmission of automatic transmission - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a gear transmission used for a speed change transmission train of an automatic transmission for a front-wheel drive vehicle with an engine placed laterally.

(Prior Art) Normally, a gear transmission of an automatic transmission is normally configured as a forward three-speed type by two sets of planetary gears, and in order to make a forward four-speed type, it is usual to add one set of planetary gears. there were.

However, in this case, the automatic transmission becomes long and it is difficult to mount it on a small vehicle. Therefore, the applicant of the present application previously disclosed in Japanese Patent Laid-Open No. 58-1
Japanese Patent No. 56753 has already proposed a technique of constructing a forward four-speed gear transmission with two sets of planetary gears.

By the way, today, the engine output is remarkably increased, and this tendency is particularly remarkable in large vehicles. For this reason, in a large-sized vehicle, it is required to further increase the number of stages of the automatic transmission, but in the above technique, the fourth forward speed is the limit.

Therefore, for speeding up to 5 speeds, the above 4
It is conceivable to add a set of speed-up planetary gears to the high speed type gear transmission.

By the way, the planetary gear for speed-up used for this purpose is, for example, as described in JP-A-59-117943, an input element,
By fixing the remaining one element of the output element and the remaining one element with a brake, a speed-up transmission state is established, and by connecting the remaining one element and the input element with a clutch, direct coupling transmission is performed. It is usual to use the one that is in a state.

Further, in this speed increasing planetary gear, which is also described in the above-mentioned publication, when the fourth speed gear transmission is shifted between the first speed and the fourth speed while maintaining the direct transmission, It is conceivable to temporarily disengage the clutch, and use the one-way clutch to put the speed-up planetary gear in the direct transmission state. In this case, the input element for inputting the output rotation of the one-way drive train during the shift, the output element for outputting the rotation to be taken out from the speed-up planetary gear, and the speed-up planetary gear when fixed are brought to the speed-up transmission state. And a brake for fixing the remaining one element, a clutch for coupling the remaining one element and the input element to bring the planetary gear for speed-up to the direct transmission state, and disengage the clutch. In this state, the one-way clutch that enables power transmission from the input element to the output element is provided, and the one-way clutch is interposed between the input element and the output element.

(Operation) For the main transmission train, it is possible to select four types of forward gears by selecting operations of various friction elements. Here, by keeping the speed increasing planetary gear in the direct coupling transmission state in which the power from the main transmission train is output as it is by engaging the clutch, the above four kinds of forward shift stages are the forward first speed to the fourth speed. .

By the way, in each of these shift speeds, the one-way clutch interposed between the input and output elements as described above restrains the meshing state between the gears forming the speed-up planetary gear,
It is possible to eliminate the influence of backlash due to backlash between these gears.

During shifting between these shift speeds, the clutch is released and the speed-up planetary gear is directly connected to the transmission state by engaging the one-way clutch, so that deceleration shock can be eliminated and shift shock countermeasures can be easily taken. .

When the speed-increasing planetary gear is switched to the speed-increasing transmission state by engaging the brake with the highest speed stage selected in the main power-train, the power from the main power-train is increased by the speed-increasing planetary gear and is output to move forward. High speed can be obtained and further multi-stages can be realized.

By the way, such a planetary gear clutch for speed increase can absorb the deceleration shock by releasing it, which makes it easy to take countermeasures against the shift shock, which is convenient.

(Problems to be Solved by the Invention) By the way, in the conventional gear transmission, the above-mentioned JP-A-
As described in Japanese Patent No. 59-117943, it is common practice to interpose the one-way clutch between the input element and the remaining one element, and there is a concern that the following problems may occur.

That is, according to the conventional arrangement of the one-way clutch, the inner race is fixed in the speed-increasing transmission state of the speed-increasing planetary gear, and as a result, the relative rotation between the inner race and the outer race becomes high speed, and the one-way clutch. It is inevitable that the durability of the will decrease.

Further, according to the conventional arrangement of the one-way clutch, in the direct transmission state of the speed-increasing planetary gear with the clutch engaged, the one-way clutch does not contribute to the meshing state between the gears forming the planetary gear, so that the backlash between the gears is not affected. There is an unavoidable effect of rattling.

An object of the present invention is to improve the gear transmission of an automatic transmission by changing the arrangement of the one-way clutch so as not to cause the above problems.

(Means for Solving the Problem) For this purpose, the present invention has two sets of planetary gears coaxially, and a transmission path of power through these planetary gears is determined by selective operation of various friction elements, and four types are selected. A planetary gear for acceleration, which has a main transmission train that can select a forward speed, and is switchable between a direct transmission state in which the power from the main transmission train is directly output and a speed-up transmission state in which the speed is increased and output. Is coaxially provided in the latter stage of the main transmission train, the inner gear of the one-way clutch rotates integrally with the input element even in the speed-up transmission state of the main transmission, and the outer race also outputs in the same direction. Since it rotates integrally with the element, the relative rotation of both races is small and the durability of the one-way clutch can be improved.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing.

FIG. 1 shows an embodiment of a gear transmission of the present invention. In the figure, E denotes an engine output shaft, 1 denotes a main transmission train, and an input shaft I of the main transmission train 1 has an engine power from a shaft E as a torque. Input via converter T / C.

The main transmission train 1 shifts and transmits the power of the input shaft I to the intermediate shaft M and is the same as that described in the above-mentioned Japanese Patent Laid-Open No. 58-156753. That is, two sets of planetary gears G ₁ , G
₂ are arranged coaxially with the axes E, I, M, and these are respectively sun gears S ₁ , S ₂ , ring gears R ₁ , R ₂ , and pinions P ₁ , P _2.
Is a simple planetary gear set consisting of three elements, carriers C ₁ and C ₂ that rotatably support C. The sun gear S ₁ can be fixed by the band brake B / B, the reverse clutch R / C can be coupled to the input shaft I, and the carrier C ₁ can be coupled to the input shaft I by the high clutch H / C. , It can be fixed by low reverse brake LR / B. Further, the carrier C ₁ can be rotated only in the same forward rotation direction as the engine by the low one-way clutch L / OWC, and can be coupled to the ring gear R ₂ by the low clutch L / C. or,
The sun gear S ₂ is connected to the input shaft I, and the carrier C ₂ is connected to the ring gear R ₁ and the intermediate shaft M.

The main transmission train 1 is a driver's desired range, that is, parking.
(P) range, reverse running (R) range, neutral (N) range, forward automatic speed change (D) range, 2nd speed engine brake (II) range, 1st speed engine brake (I) range Medium ○
By supplying hydraulic pressure to the friction element of the mark and operating it,
(However, L / OWC is mechanically self-actuated) It is possible to obtain four forward gears and one reverse gear. Band brake B /
B shall be activated when hydraulic pressure is supplied only to the fastening side, and deactivated when hydraulic pressure is also supplied to the disengagement side.

Further, the speed increasing planetary gear G ₃ downstream of the main transmission train 1 additionally installed coaxially, the planetary gear is also the sun gear S _3, the three elements of the ring gear R _3, and the carrier C ₃ which rotatably supports the pinion P ₃ It becomes a simple planetary gear set. Then, the carrier C _{3 is connected} to the intermediate shaft M to serve as an input element, and the direct gear clutch D / C can be connected to the sun gear S ₃ , so that the sun gear S ₃ is further away from the main transmission train 1 by the planetary gear G ₃ for speed-up. Overdrive brake on the terminal
It can be fixed by OD / B.

A direct one-way clutch D / OWC is separately installed between the carrier C ₃ and the ring gear R ₃ between the main transmission train 1 and the planetary gear G ₃ for speed-up, and this one-way clutch has the carrier C _{3 in the} same direction as the ring gear R _3. The carrier C ₃ is arranged so as to engage with the ring gear R ₃ when trying to rotate at a higher speed than this.

The ring gear R ₃ serves as an output element, a counter gear C / G is meshed with the outer periphery of the ring gear R ₃ , and the output shaft O of the transmission is connected to the counter gear. The counter gear C / G is arranged so as to be aligned with the direct one-way clutch D / OWC.

The speed-up planetary gear G ₃ is in an interlocked state due to the hydraulic operation of the direct clutch D / C, and the power from the main transmission train 1 to the carrier C ₃ is directly transmitted to the output shaft O via the ring gear R ₃ and the counter gear C / G. It becomes a direct connection transmission state to reach. In this transmission state, the transmissions of four types of forward movement and one type of reverse movement of the main transmission train 1 serve as the gear stages of the gear transmission of the present invention as they are.

When the overdrive brake OD / B is hydraulically operated to fix the sun gear S ₃ in the forward fourth speed selected state of the main transmission train 1, as a result of the pinion P ₃ rolling around the sun gear S ₃ ,
The speed-up planetary gear G ₃ is in a speed-up transmission state in which the power from the main transmission train 1 to the carrier C ₃ is increased to reach the output shaft O via the ring gear R ₃ and the counter gear C / G, and the fourth forward speed is established. A faster fifth forward speed can be obtained.

Incidentally, (in shifting of the main transmission sequence 1) during shifting between the planetary gear G ₃ for direct transmission state to the first speed forward obtained in the fourth speed is deactivated temporarily direct clutch D / C. In this case, if the intermediate shaft M drives the output shaft O in a power-on traveling state, the direct one-way clutch D / OWC
Although the planetary gear G ₃ is kept in the interlocked state by the operation (engagement), if the engine brake traveling state is such that the output shaft O drives the intermediate shaft M, the direct one-way clutch D / OWC is not operated ( The engine brake is not applied by idling so that deceleration shock does not occur during the gear shift.

The above operation is summarized in the table as follows.

The IV range in this table indicates the range in which the selection of the 5th speed is prohibited, and the △ mark indicates the direct one-way clutch D / OWC that operates automatically by deactivating the direct clutch D / C as described above during gear shifting. Indicates.

Especially in this example, direct one-way clutch D / OWC
Are elements S ₃ and C ₃ that are engaged by the direct clutch D / C.
Be between, among other elements, i.e. input and output elements C _3, since existing between R _3, when the first speed through the fourth speed, speed increasing planetary gear
It is also possible to obtain the effect of restraining the meshing state between the gears forming G ₃ and eliminating the influence of backlash due to backlash.

(Effects of the Invention) Thus, as described above, the gear transmission of the present invention has a clutch (D / C in the illustrated example) or a one-way clutch (D / C in the illustrated example) in the main transmission train of the forward four speed type with two sets of planetary gears. A planetary gear for speed increase is added, which is a direct transmission state by engagement of (OWC) and a speed increase transmission state by operation of the brake (OD / B in the illustrated example).
In the high-speed type, the speed-up planetary gear was coaxially arranged in the latter stage of the main transmission train, and the one-way clutch of the speed-up planetary gear was interposed between elements that were not connected by the clutch. In the direct coupling transmission state in which the clutch of the planetary gear for vehicle is engaged, the meshing state between the gears forming the planetary gear can be restrained by the one-way clutch, so that the problem of backlash due to backlash can be eliminated.

[Brief description of drawings]

FIG. 1 is a skeleton diagram showing an embodiment of a gear transmission according to the present invention. 1… Main transmission train G ₃ … Planetary gear for acceleration C ₃ … Carrier (input element) R ₃ … Ring gear (output element) S ₃ … Sun gear (remaining one element) D / C… Direct clutch D / OWC… Direct one-way Clutch (one-way clutch) OD / B ... Overdrive brake C / G ... Counter gear O ... Output shaft

Claims (1)

[Claims] 1. A main transmission train having two sets of planetary gears coaxially and capable of selecting four kinds of forward shift stages by deciding a transmission path of power passing through these planetary gears by selective operation of various friction elements. A planetary gear for speed increase that is switchable between a direct transmission state in which the power from the main transmission train is output as it is and a speed-up transmission state in which the power is output by increasing the speed is provided coaxially in the latter stage of the main transmission train. The speed-up planetary gear has an input element for inputting an output rotation of the main transmission train, an output element for outputting a rotation to be taken out from the speed-up planetary gear, and the speed-up planetary gear when the speed-up planetary gear is fixed. The remaining one element to be in the transmission state, the brake for fixing the remaining one element, and the remaining one element and the input element are coupled to each other so that the speed increasing planetary gear is brought into the direct coupling transmission state. Switch and a one-way clutch that enables power transmission from the input element to the output element even when the clutch is disengaged, and the one-way clutch is interposed between the input element and the output element. Gear transmission for automatic transmission.