JP4041078B2 - Servo link guide structure for belt type continuously variable transmission - Google Patents

Description

  The present invention relates to a guide structure of a servo link that constitutes a mechanical feedback mechanism by connecting a pulley follower, a shift control valve, and a step motor in a belt type continuously variable transmission.

Conventionally, as a continuously variable transmission suitable for vehicles, there is a belt type continuously variable transmission (hereinafter referred to as a belt CVT) using a V belt.
FIG. 3 shows an example.
The belt CVT is provided with a speed change mechanism unit 10 including a primary pulley 16 on the input shaft 15 side and a secondary pulley 26 on the output shaft 30 side as a pair of pulleys, and the input shaft 15 includes a forward / reverse switching mechanism and a lock (not shown). It is connected to the engine through a torque converter with an up clutch.
A pair of pulleys of the transmission mechanism unit 10 are connected by a V-belt 12.

The primary pulley 16 is disposed at a position facing the fixed conical plate 16a that rotates integrally with the input shaft 15 and the fixed conical plate 16a, forms a V-shaped pulley groove, and is movable in the axial direction. It is composed of a conical plate 16b.
The secondary pulley 26 is disposed at a position opposed to the fixed conical plate 26a that rotates integrally with the output shaft 30 and the fixed conical plate 26a, forms a V-shaped pulley groove, and is movable in the axial direction. The conical plate 26b is used.

A primary pulley cylinder chamber 17 and a secondary pulley cylinder chamber 27 are attached to the primary pulley 16 and the secondary pulley 26, respectively. Secondary pressure (Psec) is supplied to each.
The hydraulic control unit 5 generates a line pressure obtained by adjusting the hydraulic pressure from the oil pump OP, further adjusts the line pressure based on a command from the CVT control unit 3, and generates a primary pressure. The secondary pressure is adjusted as it is or by adjusting the line pressure.
While the vehicle is running, the groove widths of the primary pulley 16 and the secondary pulley 26 are changed by the hydraulic pressure supplied to the cylinder chambers 17 and 27, and the contact radius between the V belt 12 and the pulleys 16 and 26 is changed. The gear ratio between the primary pulley 16 and the secondary pulley 26 can be continuously changed.

  FIG. 4 shows a configuration of a primary pressure supply system to the primary pulley cylinder chamber 17 in the hydraulic control unit 5. The hydraulic control unit 5 includes a shift control valve 35 that regulates the primary pressure by adjusting the line pressure. Here, the line pressure is supplied to the secondary pulley cylinder chamber 27 as the secondary pressure.

  The shift control valve 35 is driven by a step motor 40 having a spool 36 connected to an intermediate portion of a servo link 50A constituting a mechanical feedback mechanism and connected to one end of the servo link 50A. The other end of the servo link 50A is connected to a pulley follower 45A that follows the movable conical plate 16b of the primary pulley 16. Thereby, the transmission control valve 35 receives the feedback of the groove width of the primary pulley 16, that is, the actual transmission ratio.

The gear ratio of the primary pulley 16 and the secondary pulley 26 is controlled by a step motor 40 that is driven in accordance with a shift command signal from the CVT control unit 3.
The line pressure is regulated to a predetermined value according to the operating state by a pressure regulating valve (not shown) based on a command (for example, a duty signal) from the CVT control unit 3.

Here, FIG. 5 and FIG. 6 show the conventional arrangement of the above step motor and servo link, in particular FIG. 5 is a longitudinal sectional view, and FIG. 6 is a view seen from the input shaft direction.
A guide shaft 8 is provided directly below the primary pulley 16 in the transmission case 2 between the transmission case 2 and the pulley support block 6 fixed in the transmission case in parallel to the rotation axis of the primary pulley 16. The pulley follower 45 </ b> A is slidably supported on the guide shaft 8.

The pulley follower 45 </ b> A includes a contact portion 47 that extends from the cylindrical portion 46 through which the guide shaft 8 passes to the primary pulley 16 side. When viewed from the axial direction of the guide shaft 8, the contact portion 47 has an arc shape corresponding to the outer peripheral edge of the movable conical plate 16b of the primary pulley, and contacts the surface of the movable conical plate 16b opposite to the fixed conical plate 16a. The first surface 47a is in contact with the second surface 47b, which is aligned with the outer peripheral surface of the movable conical plate 16b, and has a step-shaped cross section. Yes. The pulley follower 45A has a spring 58 disposed coaxially with the transmission case 2 so that the first surface 47a of the contact portion 47 is always pressed against the movable conical plate 16b, and the guide shaft follows the axial displacement of the movable conical plate 16b. 8. Slide on top.
The cylindrical portion 46 of the pulley follower 45A further includes a support pin 48A that supports one end of a servo link 50A described later.

The valve body 60 </ b> A is provided with a speed change control valve 35 below the guide shaft 8, and the spool 36 slides parallel to the guide shaft 8.
A step motor 40 is attached to the lower surface of the valve body 60 </ b> A, and its output rod 42 extends parallel to the guide shaft 8. The output rod 42 has a pin 43 at its tip.
An intermediate portion of the servo link 50A extending in the vertical direction is rotatably supported at the tip of the spool 36 of the speed change control valve 35, the upper end of the servo link 50A is engaged with the support pin 48A of the pulley follower 45A, and the lower end is a step. The pin 40 of the output rod 42 of the motor 40 is engaged.

  In the vicinity of the step motor 40, a link guide 63 for restricting the rotation of the servo link 50A in a plane perpendicular to the axis of the speed change control valve 35 is disposed. In this link guide 63, the engagement portion between the servo link 50A and the pin 43 of the output rod 42 of the step motor and the engagement portion of the pulley follower 45A with the support pin 48A are caught or worn by the backlash of the servo link 50A. In order to prevent the occurrence of occurrence, and in particular, to align the engagement point of the output rod 42 with the pin 43 on the shaft center of the output rod 42, thereby increasing the accuracy of the link ratio between the connection points (engagement points). It is. The link guide 63 is made of a plate material in which a slit portion 64 that sandwiches the plate thickness of the servo link 50A is formed, and is attached to the valve body 60A.

The spool 36 of the speed change control valve 35 is driven according to the displacement of the servo link 50A that responds to the step motor 40, and the speed change control valve 36 supplies and discharges hydraulic pressure to and from the primary pulley cylinder chamber 17 to drive the step motor 40. The primary pressure is adjusted to achieve the target gear ratio commanded at the position. When the movable conical plate 16b moves to complete the shift, the shift control valve 35 is closed in response to the reverse displacement of the servo link 50A.
Patent Document 1 discloses a servo link arranged in the vertical direction as described above.
JP 58-180863 A

In the conventional speed change mechanism, as described above, the posture of the servo link 50A is regulated by the link guide 63 attached to the valve body 60A. Therefore, the mounting accuracy of the link guide 63 and the product of the link guide 63 itself. Due to the error, the engagement point between the servo link 50A and the pin 43 of the output rod 42 is not always aligned with the axis of the output rod 42, and there is a problem that adjustment is difficult.
Further, since the link guide 63 is an independent part, its production and part management are also costly.

  Therefore, in view of the above problems, the present invention realizes the servo link guide of the belt-type continuously variable transmission that realizes the servo link posture restriction with simple configuration and low cost and that can guide the servo link with high accuracy. The purpose is to provide a structure.

  For this reason, the present invention makes the servo link that connects the step motor driven in response to the shift command signal and the shift control valve follow the change in the groove width of the primary pulley, and the primary pressure controlled by the shift control valve is changed to the primary pulley. In the belt-type continuously variable transmission that acts on the belt-type continuously variable transmission, the shift control valve is provided in a valve body disposed below the primary pulley, and is disposed laterally from a pulley follower that engages a movable conical plate of the primary pulley. The step motor is attached to the valve body and is arranged laterally from the pulley follower along with the speed change control valve, and the servo link extends in the lateral direction to connect the pulley follower, the speed change control valve and the step motor. On both sides of the connecting point between the servo link and the shift control valve, the support in the plane perpendicular to the shaft of the shift control valve Link guide for restricting the rotation of Borinku is assumed to be formed integrally.

For the servo link that extends in the lateral direction by engaging and connecting the pulley follower, the speed change control valve, and the step motor, the link guide formed integrally with the valve body is a servo in a plane perpendicular to the axis of the speed change control valve. Since the rotation of the link is restricted, there is no need to provide a separate link guide, and the structure is simple and low cost.
In addition, since there is no product error or mounting error in the case of separate parts, the rotation surface of the servo link can be regulated with high accuracy.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a plan view showing the embodiment, and FIG. 2 is a front view of the primary pulley as viewed from the rotation axis direction.
A guide shaft 8 is provided directly below the primary pulley 16 in the transmission case 2 in parallel with the rotation shaft of the primary pulley 16 as in the conventional example, and a pulley follower 45 is slidably supported on the guide shaft 8. Yes.

  The pulley follower 45 includes a contact portion 47 extending from the cylindrical portion 46 through which the guide shaft 8 passes to the primary pulley 16 side. When viewed from the axial direction of the guide shaft 8, the contact portion 47 has an arc shape corresponding to the outer peripheral edge of the movable conical plate 16b of the primary pulley 16, and is on the surface of the movable conical plate 16b opposite to the fixed conical plate 16a. It has the 1st surface 47a which contact | abuts, and the 2nd surface 47b aligned with the outer peripheral surface of the movable cone plate 16b.

The pulley follower 45 is engaged with the peripheral portion of the movable conical plate 16b by constantly pressing the first surface 47a of the contact portion 47 against the movable conical plate 16b by a spring 58 disposed coaxially with the transmission case 2. In this state, it slides on the guide shaft 8 according to the axial displacement of the movable conical plate 16b.
The above configuration is the same as the conventional example shown in FIG.
Next, a pin support portion 49 is provided on the cylindrical portion 46 of the pulley follower 45. In a state where the contact portion 47 is engaged with the peripheral edge portion of the movable conical plate 16b, the pin support portion 49 projects laterally (horizontal direction) and extends the pin 48 vertically downward.

The valve body 60 installed on the lower side of the primary pulley 16 bulges upward from the base portion 61 to constitute a shift control valve 35. That is, the speed change control valve 35 includes a spool hole 64 formed in the bulging portion and a spool 36 slidably disposed in the spool hole, and the spool hole 64 is substantially at the same height as the guide shaft 8 and 8 in parallel.
Further, a step motor 40 is attached to the upper surface of the valve body 60 on the opposite side of the guide shaft 8 adjacent to the speed change control valve 35, and its output rod 42 extends parallel to the guide shaft 8. As a result, the guide shaft 8, the spool shaft of the speed change control valve 35, and the shaft of the output rod 42 of the step motor 40 are arranged at substantially the same height adjacent to each other in the horizontal direction.

The output rod 42 of the step motor 40 has a bifurcated tip, and the bifurcated end is connected by a pin 43.
A block 37 having a pin hole is provided at the tip of the spool 36 of the speed change control valve 35.
The servo link 50 extends in the horizontal direction, and a pin 55 is fixed to an intermediate portion thereof. The pin 55 passes through the pin hole of the block 37 at the tip of the spool 36 from below and is prevented from being detached by a split pin. .

The servo link 50 has a plate shape and a planar shape that is linear, and both ends thereof are forked fork-shaped engaging portions 52 and 53, respectively. Then, one engaging portion 52 engages with the pin 48 with the pin 48 of the pulley follower 45 sandwiched between the two forks, and the other engaging portion 53 connects the pin 43 of the output rod 42 of the step motor 40 with 2. The pin 43 is engaged between the crotch.
The servo link 50 passes through the lower surface of the block 37 of the spool 36, while the engagement point of the output rod 42 with the pin 43 is set on the axis of the output rod 42, and is bent near the block 37 so that the cross section has a crank shape. ing.

The base portion 61 of the valve body has a planar shape and extends forward from the opening of the spool hole 64 of the speed change control valve 35, and is below the expansion / contraction range of the output rod 42 of the step motor 40 and the sliding range of the pulley follower 45. The servo link 50 whose position can be changed is covered.
In the region overlapping the servo link 50 of the base portion 61, link guides 67 and 68 are formed integrally with the base portion 61 in parallel to the axial direction of the speed change control valve 35 on both sides of the spool 36 of the speed change control valve 35. ing.

The link guide 67 rises from the base portion in a rib shape at a position corresponding to the vicinity of the engaging portion 52 of the servo link 50. The link guide 68 also rises from the base portion in a rib shape at a position corresponding to the engagement portion 52 side with respect to the bent portion of the servo link 50, but is higher than the link guide 67.
The link guides 67 and 68 have a length facing the servo link 50 at all positions that change under the expansion / contraction range of the output rod 42 and the sliding range of the pulley follower 45.
The upper surfaces of the link guides 67 and 68 are respectively machined so as to be pin-connected to the block 37 of the spool 36 and to have a set posture in which the engagement point with the pin 43 of the output rod 42 coincides with the axis of the output rod 42. Each height is set so as to contact the lower surface of the servo link 50 and support the servo link 50 in the posture state.

Other configurations are the same as in the conventional example.
The spool 36 of the speed change control valve 35 is driven according to the displacement of the servo link 50 that responds to the step motor 40, and the speed change control valve 35 supplies and discharges hydraulic pressure to and from the primary pulley cylinder chamber 17 to drive the step motor 40. The primary pressure is adjusted to achieve the target gear ratio commanded at the position. When the movable conical plate 16b moves to complete the shift, the shift control valve 35 is closed in response to the displacement of the servo link 50 in the reverse direction.

  The present embodiment is configured as described above, and the step motor 40 is arranged side by side with the speed change control valve 35 in the lateral direction from the pulley follower 45 engaged with the movable conical plate 16b of the primary pulley. The shift control valve 35 is at the same level as the pulley follower 45, and the height dimension of the belt CVT including the oil pan is remarkably shortened.

In addition, link guides 67 and 68 rising from the base 61 of the valve body are connected to both ends of the servo link 50 extending in the lateral direction by engaging and connecting the pulley follower 45, the speed change control valve 30, and the step motor 40. Since it is provided in such a manner that it is supported from below in the vicinity of the engaging portion, fluctuations in the rotation of the servo link 50 in a plane perpendicular to the shaft of the speed change control valve 35 are restricted.
In particular, since the link guides 67 and 68 are formed integrally with the valve body 60, the structure is simple and the cost is low, and unlike the case where another component having a complicated shape is mounted, product errors and mounting errors occur. Therefore, the rotation surface of the servo link 50 can be regulated with high accuracy.

  In the embodiment, the servo link 50 has a crank-like cross section. However, the servo link 50 has a straight plate shape depending on the connection structure of the speed change control valve 35 with the spool 36 and the mounting height of the step motor 40 on the valve body. For example, the shape of the link guides 67 and 68 can be set accordingly.

It is a top view which shows embodiment. It is a front view which shows embodiment. It is a figure which shows schematic structure of the transmission mechanism part of the V belt type continuously variable transmission to which this invention is applied. It is a figure which shows the concept of the mechanical feedback mechanism of a primary pulley groove width. It is a side view which shows the attachment structure of the conventional servo link. It is the figure which looked at the attachment structure of the conventional servo link from the axial direction.

Explanation of symbols

2 Transmission case 3 CVT control unit 5 Hydraulic control unit 8 Guide shaft 10 Transmission mechanism unit 12 V belt 15 Input shaft 16 Primary pulley 16a Fixed conical plate 16b Movable conical plate 17 Primary pulley cylinder chamber 26 Secondary pulley 26a Fixed conical plate 26b Movable Conical plate 27 Secondary pulley cylinder chamber 30 Output shaft 35 Shift control valve 36 Spool 37 Block 40 Step motor 42 Output rod 43, 48, 55 Pin 45 Pulley follower 46 Tube portion 47 Contact portion 47a First surface 47b Second surface 49 Pin support Part 50 Servo link 52, 53 Engagement part 58 Spring 60 Valve body 61 Base part 64 Spool hole 67, 68 Link guide OP Oil pump

Claims (3)

A belt is stretched between pulleys consisting of a primary pulley connected to the engine side and a secondary pulley connected to the output shaft to form a transmission mechanism part,
A servo link that connects the step motor driven in response to the shift command signal and the shift control valve follows the change in the groove width of the primary pulley, and applies the primary pressure controlled by the shift control valve to the primary pulley. In a step transmission,
The shift control valve is provided in a valve body disposed below the primary pulley, and is disposed laterally from a pulley follower that engages a movable conical plate of the primary pulley.
The step motor is attached to the valve body and arranged laterally from the pulley follower along with the shift control valve,
The servo link extends in the lateral direction to engage and connect the pulley follower, the shift control valve and the step motor,
The valve body is integrally formed with link guides for restricting the rotation of the servo link in a plane perpendicular to the shaft of the speed change control valve on both sides of the connecting point between the servo link and the speed change control valve. Servo link guide structure of belt type continuously variable transmission. The servo link guide for a belt-type continuously variable transmission according to claim 1, wherein the link guide is formed in a rib shape from the valve body in parallel with the axial direction of the transmission control valve. Construction. 3. The belt-type non-contact type according to claim 1, wherein the link guide is disposed at a position corresponding to the vicinity of engaging portions at both ends respectively engaged with the pulley follower and the step motor of the servo link. Servo link guide structure for step transmission.

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