JPH03244861A - Automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To perform precise shift control without worsening a shift shock by constituting a gear train so as to set the specified shift speed with a combined pattern of plural sorts of engagement and release of an engaging means, where a transmission gear ratio is the same and rotational frequency in either of rotary members differs. CONSTITUTION:A control unit consisting of a hydraulic controller C and an electric control unit E sets a shift speed on the basis of running conditions, but as to a shift speed step where there are plural sorts of engagement and release patterns, it sets the shift speed after selecting either of these patterns according to the running conditions at time of speed shifting. For example, when shift to the third gear speed is judged in a state of running at the second gear speed, whether rotational frequency of an input shaft 4 is smaller than the preset value alpha or not is judged, and when it is smaller, a pattern in a column (a) of third gear speed in a table is outputted as the engagement and release pattern for setting the third gear speed. With this constitution, variable rotational frequency of a sun gear 2S comes to 0.55 at a rate to input shaft rotational frequency, since it is thus small, it works advantageously for reducing a shift shock.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to automatic transmissions used in vehicles such as automobiles, and particularly to automatic transmissions configured to set a plurality of gears using frictional engagement means such as clutches and brakes. It is related to.

Conventional technology Automatic transmissions installed in vehicles such as automobiles have characteristics such as being small and lightweight, easy to control for shifting, and having little shift shock. It is desired that a large number of speed ratios can be set. In order to increase the number of gears that can be set, the gear train is constructed by increasing the number of planetary gear mechanisms that make up the gear train, or by increasing the number of frictional engagement means such as clutches and brakes. The configuration may be such that the connection relationship and fixed state of the rotating elements can be varied in various ways. As an example, the present applicant has constructed a gear train mainly consisting of three sets of planetary gear mechanisms, and has developed a main history of first to fifth forward speeds and reverse speeds in which the gear ratios have a relationship close to that of a geometric series. We have already proposed an automatic transmission that can set one gear, an intermediate gear between second and third gear, and an intermediate gear between third and fourth gear. In automatic transmissions, the connection relationships and fixed states of the elements of the planetary gear mechanism that make up the gear train can be varied in a variety of ways, so in addition to increasing the number of gears that can be set, There are multiple types of engagement/release (7) combination patterns (i.e., engagement/release patterns) of the frictional engagement means for setting. The engagement and release patterns include those in which the rotational speed of the rotating member does not change and those in which the rotational speed of one of the rotating members changes. Depending on the method of selection, the shift shock, shift controllability, and even the durability of the frictional engagement means will be greatly affected. Therefore, the present applicant has proposed a shift control method for an automatic transmission capable of selecting a plurality of engagement/disengagement patterns in order to set a predetermined gear position. Japanese Patent Application No. 1-280952 has already proposed a method of shifting gears by selecting an engagement/disengagement pattern so that the varying rotational speed of a rotating member during shifting is below a predetermined value.

Problem to be Solved by the Invention The ratio of the rotating member to the rotation speed of the input shaft in a gear train consisting of a plurality of planetary gear mechanisms is determined by the gear ratio of each planetary gear mechanism (ratio of the number of teeth of the sun gear to the number of teeth of the ring gear). In the conventional method described above, the rotational speed ratio of each rotating member to the input shaft determined in this way is determined according to the engagement/release state of the frictional engagement means at each gear stage. An engagement/disengagement pattern is selected whose absolute value is smaller when compared with the subsequent state.

In this way, the rotational fluctuations of the rotating members that occur with gear changes will always be small (but if the manual shaft rotational speed is small,
Correspondingly, the fluctuating rotational speed of the rotating member is also small.
There are cases where the fluctuation of the rotational speed of the rotating member due to the speed change becomes extremely small.

On the other hand, gear changes in automatic transmissions are performed by changing the engagement and release states of frictional engagement means such as clutches and brakes. cannot be accurately determined by the input shaft rotation speed or output shaft rotation speed. Therefore, conventionally,
In order to improve gear shift shock or maintain the durability of the frictional engagement means, the rotation speed of a predetermined rotating member is detected, and based on the detected value, the hydraulic pressure or engine speed to be supplied to the frictional engagement means is adjusted. Methods of controlling torque, etc. are being used. However, when such control is performed in conjunction with the above-mentioned control for selecting the engagement/disengagement pattern, when the input shaft rotation speed is small, the fluctuation in the rotation speed of a predetermined rotating member in the gear train is too small. There is a possibility that the rotation speed cannot be detected accurately. In addition, in order to avoid such inconveniences, if an engagement/disengagement pattern is selected in which the rotational speed fluctuation of the rotating member that accompanies gear change increases to a certain extent, if the input shaft rotational speed is large, the rotational fluctuation of the rotating member will be large. As a result, a problem arises in which the shift shock becomes worse.

The present invention was made against the background of the above-mentioned circumstances, and it is an object of the present invention to provide an automatic transmission capable of performing precise shift control without worsening shift shock.

Means for Solving the Problems In order to achieve the above object, the present invention provides a plurality of engagement means and an input speed ratio that is set based on the engaged/released state of these engagement means. In an automatic transmission comprising a gear train that changes the rotation speed of a shaft and transmits the changed rotation speed to an output shaft, the gear train has the same gear ratio but different rotation speeds of one of the rotating members. A combination of engagement and disengagement that is configured to set a predetermined gear stage with a plurality of combination patterns of engagement and disengagement, and that increases the fluctuating rotational speed of the rotating member when the input shaft rotational speed is smaller than a predetermined value. The predetermined gear position is set in a pattern, and the predetermined gear position is set in a combination pattern of engagement and disengagement such that the fluctuating rotational speed of the rotating member becomes small when the input shaft rotational speed is equal to or higher than a predetermined value. The present invention is characterized in that it includes a control device for controlling the vehicle.

Function: In the automatic transmission of the present invention, a predetermined gear stage can be set by a combination pattern of engagement and disengagement of mutually different frictional engagement means, and the rotational speed of a predetermined rotating member, such as a sun gear, at that gear stage can be set. differs depending on the combination pattern of engagement and release of the engagement means. The control device uses the input rotation speed for the gear train or data correlated therewith as one of the input data, and sets the engagement/disengagement combination pattern according to the input rotation speed in order to set the gear stage. change. That is, when the input rotational speed is equal to or higher than a predetermined value, an engagement/disengagement pattern is selected that reduces the rotational speed fluctuation of the rotating member that occurs when setting the gear, and the gear is set. On the other hand, when the input shaft rotational speed is smaller than the predetermined value, an engagement/disengagement pattern in which the rotational speed fluctuation of the rotating member increases is selected and the gear stage is set. Therefore, when the input shaft rotation speed is large, the fluctuation rotation of the rotating member is suppressed, so shift shock does not worsen, and when the input shaft rotation speed is small, the fluctuation rotation speed of the rotation member becomes large. However, since the input rotational speed is small, the actual rotational speed fluctuation does not become extremely large, so it is possible to accurately detect the rotational fluctuation of the rotating member without worsening the shift shock.

As a result, the transient state of the gear change can be accurately grasped, so that precise gear change control becomes possible.

Example Next, embodiments of the invention will be described with reference to the drawings.

In the example shown in Fig. 1, the gear train is constructed mainly of three sets of single pinion type planetary gear mechanisms 1, 2.3, and each element in each of these planetary gear mechanisms 1, 2.3 is as follows. It is connected and structured as follows. That is, the first
The carrier IC of the planetary gear mechanism 1 and the ring gear 3R of the third planetary gear mechanism 3 are connected to rotate together, and the ring gear 2R of the second planetary gear mechanism 2 and the carrier 3C of the third planetary gear mechanism 3 are connected so that they rotate together. Further, the sun gear IS of the first planetary gear mechanism 1 is connected to the carrier 2C of the second planetary gear mechanism 2 via the second clutch means 2, and the second planetary gear mechanism 2 is connected to the fourth clutch means via 4. sun gear 2S
and further connected to the carrier 2c of the second planetary gear mechanism 2.
is connected to the sun gear 3S of the third planetary gear mechanism 3 via a fifth clutch means 5.

Note that as a connection structure for each of the above-mentioned elements, a connection structure used in general automatic transmissions such as a hollow shaft, a solid shaft, or an appropriate connecting drum can be used.

The input shaft 4 is connected to an engine (not shown) via a power transmission means (not shown) such as a torque converter or a fluid coupling. A first clutch means 1 is provided between the input shaft 4 and the sun gear IS of the first planetary gear mechanism 1 to selectively connect the two. 3 is provided in the third clutch means.

Of the first to fifth clutch means Kl, to 5, the fourth clutch means 4 is constituted by a one-way clutch 20 and a multi-disc clutch 22 which are in a parallel relationship with each other, and the other clutch means The means is constituted by a multi-disc clutch. In addition, in practical use, since there are restrictions on the arrangement of each component, each clutch means K1. 2.
3. Of course, a suitable intermediate member such as a connecting drum may be interposed as a connecting member for 4 and 5.

Further, as a brake means for preventing the rotation of the rotating members in the above-mentioned planetary gear mechanism 1, 2.3, a first brake means Bl for selectively preventing rotation of the sun gear 3S of the third planetary gear mechanism 3, and a second A second brake means B2 that selectively blocks the rotation of the carrier 2C of the gear mechanism 2, a third brake means B3 that selectively blocks the rotation of the sun gear 2S of the second planetary gear mechanism 2, and a first planetary gear mechanism. 4th brake means B4 for selectively blocking rotation of sun gear IS 1;
and is provided. The first of these braking means
The brake means Bl is a sun gear 3 of the third planetary gear mechanism 3.
A one-way clutch 40 provided between S and a transmission case (hereinafter simply referred to as a case) 6, and a band brake 4 in parallel with this one-way clutch 40.
2, and the second brake means B
2 is a one-way clutch 6 provided between the carrier 2C of the second planetary gear mechanism 2 and the case 6 or a part integrated therewith.
0 and a multi-disc brake 61 arranged in parallel with the one-way clutch 60, and furthermore, the third brake means B3 and the fourth brake means B4 are each constituted by a band brake. In addition, in practical use, these brake means B1. B2. B3. B
4 and these brake means Bl, B2. B3. Of course, an appropriate connecting member can be interposed between each element to be fixed by B4 or between the case 6 and the case 6.

The output shaft 5 that transmits rotation to a propeller shaft and a counter gear (not shown) is connected to the ring gear 2R of the second planetary gear mechanism 2 and the gear 3C of the third planetary gear mechanism 3, which are connected to each other. connected.

Furthermore, a rotation speed sensor 7 detects the rotation speed of a member integrated with the sun gear 2S of the second planetary gear mechanism 2, for example, a cylindrical member that serves as the brake drum of the third brake means B3 and the clutch drum of the multi-disc clutch 22. is provided.

The automatic transmission having the configuration shown in FIG. 1 has five forward speeds and one reverse speed as the main gears, and between the second forward speed and the third forward speed there are so-called second and second speeds, second and third speeds. 10 forward speeds and 1 reverse speed with the addition of 5th speed and 2.7th speed, and the so-called 3.2nd speed and 3.5th speed between the 3rd and 4th forward speeds.
In principle, it is possible to set the gears of 2.2nd, 2.7th, 3.2nd, and 3.5th.
For other gears other than the above gears, there are multiple combinations of engagement and release (so-called engagement and release patterns) of the clutch means and brake means to set the gear, and these can be shown as an operation table. As shown in Table 1. Also, each planetary gear mechanism 1, 2 in each engagement/release pattern.
Table 2 shows the rotational speed of the rotating element No. 3 as a ratio when the rotational speed of the input shaft 4 is set to "1".

In Table 1, the ○ mark indicates engagement, the blank indicates disengagement, and the asterisk (*) indicates that it may be engaged. 5 Clutch means 5, first brake means Bl, etc. that do not cause a change in the gear ratio or rotational state even if released, 4th speed b
When released, like the first brake means B1 in the pattern in column b, the gear ratio does not change but the rotation state changes, and when the fourth clutch means in the pattern in column b in the second gear is released, This includes cases where the gear ratio and rotational state do not change even if the other means marked with an asterisk (*) are engaged and released. Also, in Tables 1 and 2, a
, b, c... are the engagement/disengagement patterns for which the rotational speed of the rotating element of the planetary gear mechanism differs among the engagement/disengagement patterns for setting the relevant gear. Furthermore, the symbols ■, ■, ■, .

Table 1 Table 2 Table 1 shows the gears that can be set in principle.
In practical use, the gears that are superior in terms of power performance and acceleration must be selected and set from among these gears, and specifically, the gear ratio should be close to a geometric series. The related gear will be selected as the main gear,
Also, from among the engagement/disengagement patterns listed in Table 1 for setting each gear stage, one that is advantageous in terms of shift controllability, durability, etc. is selected. Further, in the example shown in FIG. 1, since the fourth clutch means 4, the first brake means Bl, and the second brake means B2 each include one-way clutches 20, 40, and 60, the fourth clutch The engagement state of 4 in the means means that the sun gear IS of the first planetary gear mechanism 1 and the second planetary gear mechanism 2 are engaged with each other.
The one-way clutch 20 has a relative rotational direction with respect to the sun gear 2S.
If the direction of engagement is in the direction in which the one-way clutch 20 is engaged, the engaged state is maintained by the one-way clutch 20, and if the relative rotation direction is in the direction in which the one-way clutch 20 is disengaged, such as when engine braking is required, the multi-disc clutch 22 is used. 4 is engaged to bring the fourth clutch means into an engaged state. Also, the first brake means B1
Alternatively, the same applies to the second brake means B2, provided that the rotational direction of the sun gear 3S of the third planetary gear mechanism 3 or the carrier 2C of the second planetary gear mechanism 2 is the direction in which the one-way clutch 40°60 is engaged. , one-way clutch 40.6
0 is engaged to bring the first brake means B1 or the second brake means B2 into an engaged state, and when the relative rotation direction is such that engine braking is required, the one-way clutch 40.60
If it is in the releasing direction, the band brake 42 or the multi-plate brake 61 is engaged, and the first brake means Bl or the second brake means B2 is brought into the engaged state.

In the automatic transmission shown in Fig. 1, the setting of each gear stage shown in Table 1 is made according to the engine load represented by the throttle opening and the vehicle speed, as in conventional automatic transmissions. The control means includes a hydraulic control device C that supplies and discharges hydraulic pressure to engage and release each of the clutch means and brake means, and a vehicle speed V, throttle opening θ, shift position, and driving mode select signal. , and an electronic control unit (ECU) E that outputs an electrical instruction signal to the hydraulic control device c based on input data such as cooling water temperature.

The control device consisting of the hydraulic control device C and the electronic control unit E sets the gear stage based on driving conditions such as the vehicle speed ■ and the throttle opening θ. Regarding gears, the engagement/disengagement pattern is selected depending on the conditions at the time of gear shifting to set the gear.

This will be specifically explained below, taking the case of shifting from second speed to third speed as an example.

That is, FIG. 2 is a flowchart showing an example of a control routine, and when it is determined to shift to third gear due to an increase in vehicle speed or a decrease in throttle opening while the vehicle is running in second gear. (Step 1), it is determined whether the rotational speed nT of the input shaft 4 is smaller than a predetermined value α (Step 2). If the judgment result is "yes", the process proceeds to step 3 and outputs the pattern in column a of the third speed shown in Table 1 as the engagement/disengagement pattern for setting the third speed. In other words, since the second speed is set in one of the engagement/disengagement patterns in column a, by setting the third speed in the pattern in column a, the sun gear 2 of the second planetary gear mechanism 2
The variable rotation speed of S is "0.55" expressed as a ratio to the input shaft rotation speed.

Therefore, even if the rotational speed of the input shaft 4 is high, the fluctuating rotational speed of the sun gear 2S of the second planetary gear mechanism 2 becomes small, which is advantageous in reducing shift shock.

Further, in this case, the fluctuating rotational speed of the sun gear 2S does not become extremely small due to the large rotational speed of the input shaft 4, so the fluctuating rotational speed of the sun gear 2S is accurately detected by the rotational speed sensor 7. be able to. On the other hand,
If the judgment result in step 2 is "no", that is, if the input shaft 40 rotation speed is less than the predetermined value α, proceed to step 4 and use the engagement/disengagement pattern shown in Table 1 to set the third speed. Output the pattern shown in column d. This engagement
The rotational speed of the sun gear 2S in the second planetary gear mechanism 2 in the release pattern is expressed as a ratio to the rotational speed of the input shaft 4, and is "1.71°," and in the engagement/release pattern in column a of the second speed, "-1.21'', the rotational speed fluctuation is 2.92. Therefore, in this case, even if the rotational speed of the input shaft 4 is small, the range of fluctuation in the rotation of the sun gear 2S becomes large. Therefore, the actual fluctuating rotation speed of sun gear 2S becomes large to some extent, and as a result, the fluctuating rotation speed of sun gear 2S can be accurately detected by the rotation speed sensor 7. In this case, the actual fluctuating rotation speed of sun gear 2S Since the rotation speed of the input shaft 4 is small, the number is not large enough to worsen the shift shock.

Therefore, in the automatic transmission described above, at least the transient state during the shift from the second speed to the third speed is controlled by the sun gear 2.
It can be accurately grasped based on the fluctuating rotation speed of S, and as a result,
It becomes possible to accurately control the oil pressure and engine output for engaging the frictional engagement means to perform precise speed change control.

In the above embodiment, the pattern in column d was selected as the engagement/disengagement pattern for setting the third speed when the rotation speed of the input shaft 4 was small. When the rotational speed of the shaft 4 is small, the speed change control can be performed by selecting an engagement/disengagement pattern in which the rotational speed fluctuation is large. Therefore, select the engagement/disengagement pattern in column b or column C to set the third speed. Engagement/release patterns may be selected.

Furthermore, in this invention, in addition to the case of shifting from the second speed to the third speed shown in the above embodiment, the case of changing to another gear position having an engagement/release pattern with a different rotation speed of the rotating member. Shift control can be performed in the same way.

Furthermore, as is known from Table 1, in the automatic transmission shown in FIG. 1, all gears can be set without engaging the fourth brake means B4, and therefore, this invention It can also be applied to an automatic transmission equipped with a gear train having the configuration shown in which the fourth braking means B4 is omitted. This invention is equipped with a gear train that can be set in an engagement/disengagement pattern, and therefore, the present invention is applicable to, for example, Japanese Patent Application No. 1-185151, Japanese Patent Application No. 1-185152, and Japanese Patent Application No. -No. 186991,
The present invention can be applied to automatic transmissions having various configurations as described in the specifications and drawings of Japanese Patent Application No. 1-186992, Japanese Patent Application No. 1-205478, Japanese Patent Application No. 1-280957, and the like.

Effects of the Invention As is clear from the above explanation, in the automatic transmission of the present invention, when setting a predetermined gear, it is not necessary to uniformly select an engagement/disengagement pattern in which the fluctuating rotational speed of the rotating member is small. If the rotation speed of the input shaft is smaller than 10, an engagement/disengagement pattern is selected in which the ratio of the variable rotation speed to the rotation speed of the input shaft is large. The rotational speed becomes large enough not to worsen the shift shock, and therefore, the fluctuating rotational speed of the rotating member can be accurately detected and used as data for shift control, so shift control can be performed precisely and, in turn, shift shock can be reduced. The durability of the frictional engagement means can be further improved than before.

[Brief explanation of drawings]

FIG. 1 is a skeleton diagram showing the principle of an embodiment of the present invention, and FIG. 2 is a flowchart showing an example of a control routine for shifting from second to third speed executed in the automatic transmission. It is. 1.2.3...Planetary gear mechanism, IS, 23,3S・
...Sun gear, IC, 2C, 3C...Carrier,
IR, 2R, 3R...Ring gear, 4...Input shaft, 5...Output shaft, 7...Rotation speed sensor, C...
・Hydraulic control device, E...Electronic control unit.

Claims (1)

[Claims] A gear that changes the rotational speed of an input shaft in accordance with a plurality of engagement means and a gear ratio that is set based on the engagement/disengagement state of these engagement means and transmits the rotation speed to the output shaft. In the automatic transmission, the gear train is configured to perform a predetermined speed change using a plurality of engagement/disengagement combination patterns of the engagement means having the same gear ratio but different rotational speeds of one of the rotating members. The predetermined gear is configured to set the predetermined gear, and the predetermined gear is set with a combination pattern of engagement and disengagement in which the fluctuating rotational speed of the rotating member increases when the input shaft rotational speed is smaller than a predetermined value, and the input shaft A vehicle characterized by comprising a control device that controls the predetermined gear stage to be set using a combination pattern of engagement and disengagement in which the fluctuating rotational speed of the rotating member becomes smaller when the rotational speed is equal to or higher than a predetermined value. automatic transmission.