JPH02173471A - Band servo device for automatic transmission - Google Patents

Abstract

PURPOSE:To enable free setting to be attained of a position by providing an actuator to be arranged almost in parallel with the center of a rotary shaft of a rotary drum in a manner, wherein an acting direction of the actuator is orthogonal with the direction of a brake band in its connecting and releasing action, and suitably setting an arranging position of the actuator, shape of a direction change lever and its length. CONSTITUTION:A brake band 33, supported in its fixed end part 33a by an anchor end pin 6 fixed to a transmission case further in the movable end part 33b by a strut 7, is tightened to a rotary drum by moving the strut 7 in its stroke to the left direction. And a hydraulic actuator 8 is arranged so that its operating direction (b) is in a direction parallel with an axial direction (a) of the rotary drum further orthogonal with an operating direction (c) of the brake band 33. While a piston stem 8a is connected being able to transmit drive power to the strut 7 through a direction change lever 9. By this constitution, a position for providing the hydraulic actuator 8 can be freely set by suitably setting a shape of the direction change lever 9 and its length.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a band servo device that engages or releases a brake band, which is one of the engagement elements of an automatic transmission, with respect to a rotating drum.

(Prior Art) Conventionally, as a band servo device for an automatic transmission, for example,
“Complete Book of Automotive Engineering Volume 9 Power Transmission Device (November 1980)
The one described on pages 224 and 225 of ``Published by Sankai-muro (Sankaishiro) on March 15th is known.

This conventional device includes a brake band wound around a rotating drum of a transmission mechanism, and an actuator that engages or releases the brake band with respect to the rotating drum. As the actuator, a hydraulic actuator is used, which includes a piston stem connected to the working end of the brake band, and a servo piston to which the piston stem is fixed and is slidably provided with respect to the piston cylinder. was.

(Problem to be Solved by the Invention) However, in the conventional device as described above, the actuator operates in the same direction as the actuation direction of the brake band (the actuation direction is relative to the axial direction of the rotating drum). Therefore, the position where this actuator is installed is limited to the position in the radial direction of the brake band, resulting in a problem that the degree of freedom in design is low.

Further, as described above, since the actuating direction of the actuator is orthogonal to the axial direction of the rotating drum, the actuator may protrude laterally with respect to the automatic transmission.

For this reason, when applied to an FR type vehicle, for example, a problem arises in that the actuator interferes with the floor of the vehicle body or the floor tunnel.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a band servo device for an automatic transmission that has a high degree of freedom in design and allows for a layout that does not easily interfere with the floor of a vehicle body, a floor tunnel, etc.

(Means for Solving the Problems) In order to achieve the above object, the band servo device for an automatic transmission of the present invention includes a brake band wound on the outer periphery of a rotating drum of an automatic transmission, and a brake band wound on the outer circumference of a rotating drum of an automatic transmission. A band servo device for an automatic transmission comprising: an actuator that engages or releases a brake band with respect to a rotating drum;
An actuator is disposed substantially parallel to the rotational axis of the rotary drum so as to be orthogonal to the release operation direction, and the actuator and the brake band are coupled by a direction change lever so that driving force can be transmitted. It was a means to do so.

(Function) In the band servo device for an automatic transmission of the present invention, the actuator is disposed so that its operating direction is substantially parallel to the axial direction of the rotating drum, and the actuator is connected to the brake band via a direction change lever. are combined.

Therefore, the arrangement position of the actuator is not limited to the radial position of the brake band, and can be freely set by appropriately setting the shape and length of the direction conversion lever.

At the same time, since the actuator operates in the axial direction of the rotating drum, the amount by which the actuator projects in the radial direction of the rotating drum can be kept small.

(Example) Embodiments of the present invention will be described below based on the drawings.

In describing this embodiment, an automatic transmission for an FR vehicle will be taken as an example.

First, the configuration will be explained.

FIG. 2 is a side view showing the external appearance of a power unit including an automatic transmission equipped with a band servo device A for an automatic transmission according to an embodiment of the present invention, in order from the parts located at the front of the vehicle, 1 is Engine, 2 is converter housing, 3
is the transmission case, 4 is the rear extension, and 5 is the output shaft.

A speed change mechanism 31 is provided within the transmission case 3, and a rotating drum 32 shown in FIG. 1 is provided at the rearmost portion of the speed change mechanism 31. A brake band 33 is wound around the outer circumference of this rotating drum 32.

The brake band 33 has a fixed end 33a supported by an anchor end pin 6 fixed to the transmission case 3, and a movable end 33b supported by a strut 7, so that the strut 7 moves leftward in the figure. It is fastened to the rotating drum 32 by stroking. By this fastening, the rotating drum 32 is fixed to the transmission case 3. That is, arrow C is the direction in which the brake band 33 is engaged and released.

Note that the strut 7 is connected to the transmission case 3.
The support protrusion 34 is slidably supported in the left-right direction (vehicle width direction) in the figure. Further, the transmission case 3 is arranged within a floor tunnel FT that constitutes the vehicle body.

Sliding of the strut Y is achieved by a hydraulic actuator 8. As shown in FIG. 2, this hydraulic actuator 8 is attached to the outside of the rear extension 4, and as shown in FIG. 3, it has a piston stem 8a, a servo piston 8b, and a return spring 8C.
The structure is such that the servo piston 8b slides with respect to the piston cylinder 8f by guiding the control hydraulic pressure to the pressure chambers 8d and 8e.

The piston stem 8a is connected to the rotating drum 3.
The sliding direction of the servo piston 8b, that is, the operating direction of the hydraulic actuator 8 is parallel to the axial direction of the rotating drum 32, and the operating direction of the brake band 33 is parallel to the axial direction a of the rotary drum 32. It is arranged in a direction perpendicular to direction C.

Therefore, as shown in FIG. 1, the hydraulic actuator 8 is arranged to overlap the rotating drum 32 and the brake band 33 in the longitudinal direction of the vehicle.

The piston stem 8a is coupled to the strut 7 via a direction change lever 9 so as to be capable of transmitting driving force.

That is, the direction change lever 9 is formed in a substantially "<" shape, and has an intermediate portion rotatably supported by the transmission case 3 by a pin 9a, and one end connected to the tip of the piston stem 8a. inserted into the connecting groove 89,
The other end is inserted into the connection groove 78 at the proximal end of the strut 7, and the insertion into the reconnection grooves 7a and 8g is rotatable while allowing displacement of the pin 9a in the radial direction. ing.

Further, as shown in FIG. 1, the other end of the direction changing lever 9 is bent downward at a right angle.

Incidentally, a parking brake pole 41 is attached to the inside of the front end of the rear extension 4, as shown in FIG. This parking brake pole 41 has one end rotatably attached to the rear extension 4, and a protrusion 41a on the other end.
is formed so as to be able to mesh with the bark gear 10, and in this meshed state, the output shaft 5 is fixed to the rear extension 4.

Further, the parking brake pawl 41 is biased in the disengagement direction by the return spring 41b, and reaches the engaged state by the sliding of the parking rod 42 when the P range is selected with a control lever (not shown). It is designed to be rotated.

One end of this parking rod 42 is supported by a support 43.

That is, the lower end of this support 43 has an engaging protrusion 43a.
By forming the engaging protrusion 43a, the parking clot 42 is formed so that it will not fall off from the support 43 when a travel range including the N range other than the P range is selected. .

That is, by forming this engagement protrusion 43a, the rod guide for supporting the parking lot 42, which was conventionally necessary, is eliminated, thereby achieving a simplified structure and a reduction in the number of parts.

Next, the operation of the embodiment will be explained.

When the control hydraulic pressure is introduced into the pressure chamber 8d of the piston cylinder 8f of the hydraulic actuator 8, the servo piston 8b and the piston stem 8a slide toward the rear of the vehicle (downward in FIG. 3), which causes the direction change lever 9 to move in the direction of arrow d. , and stroke the strut 7 to the left in the figure.

The stroke of this strut 7 causes the brake band 3 to
3 is fastened, and the rotating drum 32 is fixed to the transmission case 3.

Furthermore, when the control hydraulic pressure is introduced into the pressure chamber 8e of the hydraulic actuator 8, the servo piston 8b and the piston stem 8
a slides toward the front of the vehicle, the strut 7 strokes to the right in the figure, and the brake band 33 is released.

Since the automatic transmission pandosurf device according to the embodiment of the present invention is constructed as described above, the effects described below are simultaneously achieved.

■ The hydraulic actuator 8 is arranged so that the axial direction and sliding direction (actuation direction) of the piston stem 8a are parallel to the axial direction a of the rotating drum 32, and the brake band 3
3, since the hydraulic actuator 8 is connected via the direction change lever 9, the installation position of the hydraulic actuator 8 is no longer limited to the radial position of the brake band 33, and the shape and length of the direction change lever 9 can be changed. By making appropriate settings, the position where the hydraulic actuator 9 is provided can be freely set. In other words, the effect of increasing the degree of freedom in design can be obtained.

(2) Since the amount by which the rotating drum 32 protrudes in the radial direction can be kept small, it is possible to prevent interference with vehicle body side members such as the floor of the vehicle body and the floor tunnel FT.

Although the embodiment has been described above based on the drawings, the specific configuration is not limited to this embodiment, and even if there is a design change within the scope of the gist of the present invention, it is included in the present invention. .

For example, in the example, an example was shown in which it was applied to an FR vehicle, but
It can also be applied to other types of vehicles such as FF vehicles with horizontally mounted engines and 4WD vehicles.

(Effects of the Invention) As explained above, in the band servo device for an automatic transmission of the present invention, the actuator is disposed so that its operating direction is substantially parallel to the axial direction of the rotating drum, and
By connecting the actuator to the brake band via the direction change lever, the actuator's installation position is not limited to the radial position of the brake band, and the shape and length of the direction change lever can be set as appropriate. As a result, the position of the actuator can be set freely, which has the effect of increasing the degree of freedom in design, and at the same time, the amount by which the actuator protrudes in the radial direction relative to the rotating drum can be kept small. It is possible to prevent interference with surrounding car bodies, and especially in E-day cars (vehicles with vertical engine installation), it is possible to prevent interference with the floor and floor tunnel.

Furthermore, by being able to prevent such interference, an effect can be obtained in that the vehicle interior space can be expanded by that much.

[Brief explanation of the drawing]

Fig. 1 is a sectional view from the rear side of a vehicle showing a band servo device for an automatic transmission according to an embodiment of the present invention, Fig. 2 is a side view showing a power unit including the embodiment device, and Fig. 3 is a side view showing the embodiment device. FIG. 4 is a sectional view taken from the bottom side, and FIG. 4 is a perspective view showing the main parts of the apparatus according to the embodiment. 8...-Hydraulic actuator 9...Direction conversion lever 32...Rotating drum 33...Brake band a...Axial direction of rotating drum b...Operation direction of actuator C...-Tightening of brake band・Patent application for release operation direction Japan Automatic Transmission Co., Ltd. Nissan Motor Co., Ltd.

Claims (1)

[Claims] 1) A band servo for an automatic transmission comprising: a brake band wound around the outer periphery of a rotating drum of the automatic transmission; and an actuator that engages or releases the brake band with respect to the rotating drum. In the device, the actuator is disposed approximately parallel to the rotational axis of the rotating drum so that the operating direction of the actuator is perpendicular to the direction of engagement and release of the brake band, and the actuator and the brake band are changed in direction. A band servo device for an automatic transmission, characterized in that the band servo device is connected to a lever so that driving force can be transmitted.