JP6090262B2 - Automatic transmission - Google Patents

Description

  The present invention relates to an automatic transmission that includes a fluid transmission device and a hydraulic pump that is driven by an engine through a case of the fluid transmission device.

  In general, an automatic transmission mounted on an automobile using an engine as a drive source includes a transmission mechanism that changes engine output, a fluid transmission device that transmits engine output to the transmission mechanism, and between the transmission mechanism and the fluid transmission device. And a hydraulic pump for supplying hydraulic oil to them. The driving force output from the transmission mechanism is transmitted to the differential device, thereby driving the axle connected to the drive wheels.

  Furthermore, for example, as disclosed in Patent Document 1, a general automatic transmission is configured as follows. That is, the case of the fluid transmission device provided in the automatic transmission has a front cover that forms the engine side surface and a pump shell that forms the anti-engine side surface. At the center of the front cover, a boss for centering the fluid transmission device with respect to the crankshaft that is the output shaft of the engine is provided. The boss is fitted into a centering hole provided at the end of the crankshaft when the automatic transmission is assembled to the engine. A plurality of bolts are provided on the outer peripheral portion of the front cover, and the front cover is attached to the outer peripheral portion of the drive plate attached to the end portion of the crankshaft by the bolts. As a result, the entire torque converter is connected to the crankshaft and driven by the engine. On the other hand, a sleeve for driving the hydraulic pump is provided at the center of the pump shell.

  The hydraulic pump is an internal gear meshing type gear pump formed by combining an inner rotor and an outer rotor arranged eccentrically with each other. Two parallel surfaces are provided on the inner peripheral surface of the inner rotor and the outer peripheral surface of the tip of the sleeve so as to engage with each other. When the automatic transmission is assembled, the tip of the sleeve is fitted into the inner rotor, and these two parallel surfaces are engaged.

  The output of the engine is input to the case of the fluid transmission device via the crankshaft, whereby the inner rotor and the sleeve engaged as described above rotate as a unit. Along with this rotation, the volume of each space formed in the gap between the inner rotor and the outer rotor periodically increases / decreases. When the volume increases, the hydraulic oil is sucked from the suction port, and when the volume decreases, the hydraulic oil is discharged from the discharge port.

JP-A-8-226519

  By the way, in the case of the fluid transmission device provided in the automatic transmission of Patent Document 1, a plurality of welds exist between the front cover and the pump shell, between the pump shell and the sleeve, and the like. It is difficult to increase the concentricity between the boss and the sleeve due to the centering error in the welded portion and the dimensional tolerance between the front cover and the pump shell.

  However, in a state where the coaxiality between the boss and the sleeve is low, the sleeve is swung when the engine is driven, so that the inner rotor of the hydraulic pump to which the sleeve is fitted rotates while the center of rotation moves. become. As a result, the inner rotor receives a force in the radial direction from the sleeve, and the outer rotor that meshes with the inner rotor is partially pressed strongly against the housing of the hydraulic pump. As a result, the following problems are assumed. First, the outer rotor pressed against the housing becomes a resistance, resulting in an increase in engine driving loss, that is, a reduction in fuel consumption. Furthermore, it is conceivable that the abrasion generated in the gears and sleeves of the hydraulic pump becomes severe. Second, the rotation of the hydraulic pump becomes unstable, and hydraulic vibration is generated in the discharge pressure of the hydraulic oil supplied to the transmission and the fluid transmission.

  In order to solve these problems, in the torque converter manufacturing process, the coaxiality between the boss provided on the engine side surface of the case and the sleeve provided on the anti-engine side surface may be increased. In addition, it is necessary to increase the dimensional accuracy at the time of manufacturing and welding of each member, resulting in a decrease in productivity and an increase in manufacturing cost.

  Accordingly, the present invention relates to an automatic transmission that includes a fluid transmission device and a hydraulic pump that is driven by the engine through a case of the fluid transmission device, while suppressing an increase in manufacturing cost and driving loss of the engine. It is an object of the present invention to suppress the increase in hydraulic pressure and the hydraulic vibration in the discharge pressure of the hydraulic pump.

  In order to solve the above problems, the present invention is configured as follows.

The invention described in claim 1
An automatic transmission comprising a fluid transmission device and a hydraulic pump provided on a side opposite to the engine of the fluid transmission device and driven by the engine through a case of the fluid transmission device;
The case of the fluid transmission device has a boss fitted into a centering hole provided at an end of a crankshaft of the engine, and a sleeve having a tip fitted into an inner rotor of the hydraulic pump,
A sleeve side engaging portion that engages with a rotor side engaging portion provided on an inner peripheral surface of the inner rotor and a rotor side engaging portion on the inner peripheral surface of the inner rotor are provided on the outer peripheral surface of the distal end portion of the sleeve. A sleeve-side non-engaging portion facing the removed rotor-side non-engaging portion is provided,
A clearance between the sleeve-side non-engaging portion and the rotor-side non-engaging portion is characterized by becoming larger toward the tip of the sleeve.

The invention according to claim 2 is the automatic transmission according to claim 1,
In the sleeve side non-engagement portion, the outer diameter of the sleeve decreases toward the tip of the sleeve, so that the clearance increases toward the tip of the sleeve.

The invention according to claim 3 is the automatic transmission according to claim 1 or 2,
The inner diameter of the inner rotor increases toward the tip of the sleeve at the rotor-side non-engagement portion, so that the clearance increases toward the tip of the sleeve.

  According to the first aspect of the present invention, the clearance between the rotor-side non-engaging portion and the sleeve-side non-engaging portion increases toward the tip of the sleeve, so that the inner diameter of the hydraulic pump received from the sleeve is increased. Directional force is reduced. Accordingly, it is possible to suppress an increase in engine driving loss and hydraulic vibration in the discharge pressure of the hydraulic pump while suppressing an increase in manufacturing cost due to an improvement in the coaxiality between the boss and the sleeve.

  According to the second aspect of the present invention, the effect of the first aspect can be specifically achieved simply by processing the sleeve.

  According to the third aspect of the present invention, the effect of the first aspect can be specifically achieved only by processing the inner rotor. Further, by applying the invention according to claim 3 to the automatic transmission according to claim 2, the effect of claim 1 can be obtained more reliably.

It is sectional drawing which shows a part of structure of the automatic transmission which concerns on embodiment of this invention. It is sectional drawing which shows the fitting state of the sleeve of a torque converter case, and the inner rotor of a hydraulic pump. It is a disassembled perspective view which shows the fitting state of the sleeve of a torque converter case, and the inner rotor of a hydraulic pump. It is sectional drawing which shows a part of structure of the automatic transmission which concerns on the 1st modification of this invention. It is sectional drawing which shows a part of structure of the automatic transmission which concerns on the 2nd modification of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing a part of the structure of an automatic transmission 1 according to an embodiment of the present invention.
The automatic transmission 1 is an example of a fluid transmission device mounted on an automobile having an engine as a drive source, and includes a torque converter 2, a hydraulic pump 3, and a transmission mechanism (not shown) from the engine side. The automatic transmission 1 includes a turbine shaft 4 that functions as an output shaft of the torque converter 2 and an input shaft of the speed change mechanism.

  The torque converter 2 includes a pump, a turbine, a stator, a one-way clutch, a lock-up clutch, a lock-up damper, and the like as main components inside the torque converter case 20, but some or all of them are shown in FIG. The illustration is omitted, and the description thereof is also omitted.

  The torque converter case 20 includes a front cover 21 that forms an engine side surface, and a pump shell 22 that forms an anti-engine side surface and forms an outer shell of the pump. Although not shown, the front cover 21 and the pump shell 22 are welded at the outer periphery. A plurality of bolts are fixed concentrically on the outer periphery of the front cover 21, and the front cover 21 is attached to the outer periphery of the drive plate attached to the end of the crankshaft 10 by these bolts. As a result, the entire torque converter 2 is connected to the crankshaft 10 and rotates integrally with the crankshaft 10.

  The front cover 21 has a boss 23 provided at the center thereof. The boss 23 is fitted into the centering hole 11 provided at the end of the crankshaft 10 when the automatic transmission 1 is assembled to the engine. As a result, the torque converter 2 is centered with respect to the crankshaft 10. In FIG. 1, the axis X of the crankshaft 10 is shown with a symbol X. The end of the turbine shaft 4 is fitted inside the boss 23. The above speed change mechanism is provided on the axis of the turbine shaft 4, whereby the output rotation of the torque converter 2 is input to the speed change mechanism via the turbine shaft 4.

  A sleeve 24 extending toward the non-engine side is welded to an inner peripheral end portion of the pump shell 22. A parallel two-surface portion 24 a is provided on the outer peripheral surface of the distal end portion of the sleeve 24. Further, a tapered surface portion 24b is provided in a portion of the outer peripheral surface of the distal end portion of the sleeve 24 where the two-surface portion 24a is not provided, and the outer diameter of the sleeve 24 is set to the distal end (anti-engine side). ) Is becoming smaller.

  The hydraulic pump 3 is an internal gear mesh type gear pump, and is housed in a pump housing 31 fixed to a transmission case (not shown), a pump cover 32 provided on the engine side, and a gap formed therebetween. A pair of inner rotor 33 and outer rotor 34 are provided. The inner rotor 33 and the outer rotor 34 are arranged eccentric to each other. When the automatic transmission 1 is assembled, the inner rotor 33 is fitted with the tip of the sleeve 24 of the torque converter case 20 inserted. Similar to the sleeve 24, a parallel two-surface portion 33 a is provided on the outer peripheral surface of the inner rotor 33.

2 and 3 are a cross-sectional view and an exploded perspective view showing a fitting state between the sleeve 24 of the torque converter case 20 and the inner rotor 33 of the hydraulic pump 3, respectively.
As shown in the drawing, when the front end portion of the sleeve 24 is fitted to the inner rotor 33, the two surface portions 33a of the inner rotor 33 and the two surface portions 24a of the sleeve 24 are engaged with each other. Further, a portion (referred to as an inner peripheral surface portion) 33 b where the two surface portions 33 a are not provided on the inner peripheral surface of the inner rotor 33 and the tapered surface portion 24 b of the sleeve 24 are opposed to each other. In this facing portion, the clearance between the inner peripheral surface portion 33 b of the inner rotor 33 and the tapered surface portion 24 b of the sleeve 24 increases toward the tip of the sleeve 24.

  In the above-described embodiment, the two-surface portion 33a and the inner peripheral surface portion 33b of the inner rotor 33 correspond to examples of the rotor-side engaging portion and the rotor-side non-engaging portion, respectively. The two surface portions 24a and the tapered surface portion 24b of the sleeve 24 correspond to an example of a sleeve side engaging portion and a sleeve side non-engaging portion, respectively.

  According to the configuration of the automatic transmission 1, when the engine is driven, the output is input to the front cover 21 of the torque converter case 20 via the crankshaft 10, and the entire torque converter 2 rotates. The sleeve 24 joined to the pump shell 22 of the torque converter case 20 and the inner rotor 33 of the hydraulic pump 3 fitted with the tip of the sleeve 24 are integrated with each other by the engagement of these two surface portions 24a and 33a. And rotate. With this rotation, the hydraulic pump 3 sucks and discharges hydraulic oil. Further, the output rotation of the torque converter 2 is input to the transmission mechanism via the turbine shaft 4.

  Here, in a state where the coaxiality between the boss 23 of the front cover 21 and the sleeve 24 joined to the pump shell 22 is low, the sleeve 24 swings and the inner rotor 33 of the hydraulic pump 3 rotates while its rotational center moves. Will do. At this time, as in the present embodiment, the clearance between the inner peripheral surface portion 33 b of the inner rotor 33 and the tapered surface portion 24 b of the sleeve 24 is increased toward the tip of the sleeve 24, so that the inner rotor 33 is moved to the sleeve 24. As a result, the force received in the radial direction from the engine is reduced, and as a result, an increase in engine drive loss and hydraulic vibration in the discharge pressure of the hydraulic pump 3 are suppressed.

  Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment. In addition, various modifications and improvements may be added to the above-described embodiment, and thus there are various modifications in the present invention.

  For example, as shown in FIG. 4 as a first modification, the inner rotor 133 is not provided with a tapered surface in a portion (referred to as an outer peripheral surface portion) 125b in which the two surface portions 124a are not provided in the outer peripheral surface of the sleeve 124. A reverse taper surface portion 133b may be provided in a portion of the inner peripheral surface where no two surface portions are provided. According to this configuration, the inner diameter of the inner rotor 133 increases toward the tip of the sleeve 124, and the clearance between the reverse tapered surface portion 133 b of the inner rotor 133 and the outer peripheral surface portion 124 b of the sleeve 124 increases toward the tip of the sleeve 124. Thus, the same effect as that of the above-described embodiment can be obtained.

  FIG. 4 showing the first modification and FIG. 5 showing the next second modification show a part of FIG. 1, but many of the configurations shown in FIG. 1 are not shown. ing. Also, the alternate long and short dash line with the symbol X indicates the axis of the crankshaft 10 as in FIG.

  Further, as shown in FIG. 5 as a second modification, a tapered surface 224b is provided in a portion of the outer peripheral surface of the tip portion of the sleeve 224 where the two-surface portion 224a is not provided, and the inner peripheral surface of the inner rotor 233 is further provided. Of these, the reverse taper surface portion 233b may be provided in a portion where the two surface portions are not provided. That is, the second modification has a configuration in which the above-described embodiment and the first modification are combined, and the effect of the above-described embodiment can be more reliably obtained by this configuration.

  As described above, according to the present invention, it is possible to suppress an increase in engine drive loss and hydraulic vibration in the discharge pressure of the hydraulic pump while suppressing an increase in the manufacturing cost of the automatic transmission. This type of automatic transmission may be suitably used in the manufacturing industry.

1 Automatic transmission 2 Torque converter (fluid transmission)
3 Hydraulic Pump 10 Crankshaft 11 Centering Hole 20 Torque Converter Case 21 Front Cover 22 Pump Shell 23 Boss 24 Sleeve 24a Two Sides (Sleeve Side Engagement Part)
24b Tapered surface portion (non-engaging portion on the sleeve side)
33 Inner rotor 33a Two-surface part (rotor side engaging part)
33b Inner peripheral surface portion (rotor side non-engaging portion)
34 Outer rotor

Claims (3)

An automatic transmission comprising a fluid transmission device and a hydraulic pump provided on a side opposite to the engine of the fluid transmission device and driven by the engine through a case of the fluid transmission device;
The case of the fluid transmission device has a boss fitted into a centering hole provided at an end of a crankshaft of the engine, and a sleeve having a tip fitted into an inner rotor of the hydraulic pump,
A sleeve side engaging portion that engages with a rotor side engaging portion provided on an inner peripheral surface of the inner rotor and a rotor side engaging portion on the inner peripheral surface of the inner rotor are provided on the outer peripheral surface of the distal end portion of the sleeve. A sleeve-side non-engaging portion facing the removed rotor-side non-engaging portion is provided,
The automatic transmission according to claim 1, wherein a clearance between the sleeve-side non-engaging portion and the rotor-side non-engaging portion increases toward the tip of the sleeve. In the sleeve-side non-engaging portion, the outer diameter of the sleeve decreases toward the tip of the sleeve, so that the clearance increases toward the tip of the sleeve,
The automatic transmission according to claim 1. In the rotor-side non-engaging portion, the inner diameter of the inner rotor increases toward the tip of the sleeve, whereby the clearance increases toward the tip of the sleeve,
The automatic transmission according to claim 1 or 2.

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