Device for locking a piston rod of a piston of an actuator which is pressurizable in order to disengage a parking lock and is spring-loaded in order to engage the parking lock

Abstract

A device for locking a piston rod of a piston of an actuator is provided. An electrically actuatable electromagnet includes an armature rod, which is axially movable counter to a first preloading spring and on which two actuating elements are axially displaceably mounted between two stops of the armature rod. A second preloading spring is axially mounted between the two actuating elements. The actuating elements each include actuating contours, which are associated with latching mechanisms, via which the piston is mechanically fixable in a disengaged condition and in a engaged condition of the parking lock.

Claims

1. A device (2; 203) for locking a piston rod (7) of a piston (4) of an actuator, which is pressurizable in order to disengage a parking lock (3), the device (2; 203) comprising: an electrically actuatable electromagnet (19) with an armature rod (20) that is axially movable against a spring force of a first preloading spring (21); two actuating elements (37, 38) axially displaceably mounted on the armature rod (20) axially between two stops (35, 36) of the armature rod (20); and a second preloading spring (39) axially mounted between the two actuating elements (37, 38), wherein the actuating element (37) positioned proximate the electromagnet (19) comprises an actuating contour (22) facing the electromagnet (19), the actuating contour (22) of the actuating element (37) positioned proximate the electromagnet (19) associated with a first latching mechanism (24), the piston (4) mechanically fixable in a disengaged condition of the parking lock (3) with the first latching mechanism (24), wherein the actuating element (38) positioned remote from the electromagnet (19) comprises an actuating contour (23) facing away from the electromagnet (19), the actuating element (38) positioned remote from the electromagnet (19) associated with a second latching mechanism (25), the piston (4) mechanically fixable in an engaged condition of the parking lock (3) with the second latching mechanism (25), wherein both of the first and second latching mechanisms (24, 25) are centrally arranged within the piston (4), interlocking elements (28, 29) of the first and second latching mechanisms (24, 25) are disposed in a housing-affixed component (30) in an axially fixed manner, and the interlocking elements (28, 29) are radially displaceable with respect to the component (30) and selectively engageable with the piston (4) by a respective actuating contour (22, 23), wherein components of the device (2; 203) are coordinated with respect to geometry and with respect to forces acting upon each of the components such that the actuating contour (23) facing away from the electromagnet (19) blocks movement of the interlocking elements (29) of the second latching mechanism (25) when the parking lock (3) is in the engaged condition of the parking lock (3) and the electromagnet (19) is in a non-energized condition of the electromagnet (19), the actuating contour (23) facing away from the electromagnet (19) releases the interlocking elements (29) of the second latching mechanism (25) for movement when the electromagnet (19) is in an energized condition of the electromagnet (19), the actuating contour (22) facing the electromagnet (19) blocks movement of the interlocking elements (28) of the first latching mechanism (24) when the parking lock (3) is in the disengaged condition of the parking lock (3) and the electromagnet (19) is in the energized condition of the electromagnet (19), and the actuating contour (22) facing the electromagnet (19) releases the interlocking elements (28) of the first latching mechanism (24) for movement when the electromagnet (19) is in the non-energized condition of the electromagnet (19).

2. The device of claim 1, wherein the components of the device (2; 203) are coordinated with respect to the geometry and with respect to the forces acting upon each of the components such that, when the electromagnet (19) is in the non-energized condition of the electromagnet (19) and the parking lock (3) is in the engaged condition of the parking lock (3), the first and second preloading springs (21, 39) hold the armature rod (20) and the actuating element (38) positioned remote from the electromagnet (19) in axial positions at which the interlocking elements (29) of the second latching mechanism (25) at least partially engage into the piston (4) and block movement of the piston (4).

3. The device of claim 1, wherein the components of the device (2; 203) are coordinated with respect to the geometry and with respect to the forces acting upon each of the components such that, when the electromagnet (19) is in the energized condition of the electromagnet (19) and the parking lock (3) is in the engaged condition of the parking lock (3), the electromagnet (19) holds the armature rod (20) and the actuating element (38) positioned remote from the electromagnet (19) counter to the first and second preloading springs (21, 39) in axial positions at which the interlocking elements (29) of the second latching mechanism (25) are guidable out of engagement with the piston (4) to release the piston (4) for movement.

4. The device of claim 1, wherein the components of the device (2; 203) are coordinated with respect to the geometry and with respect to the forces acting upon each of the components such that, when the electromagnet (19) is in the non-energized condition of the electromagnet (19) and the parking lock (3) is in the disengaged condition of the parking lock (3), the first and second preloading springs (21, 39) hold the armature rod (20) and the actuating element (37) positioned proximate the electromagnet (19) in axial positions at which the interlocking elements (28) of the first latching mechanism (24) are guidable out of engagement with the piston (4) to release the piston (4) for movement.

5. The device of claim 1, wherein the components of the device (2; 203) are coordinated with respect to the geometry and with respect to the forces acting upon each of the components such that, when the electromagnet (19) is in the energized condition of the electromagnet (19) and the parking lock (3) is in the disengaged condition of the parking lock (3), the electromagnet (19) holds the armature rod (20) and the actuating element (37) positioned proximate the electromagnet (19) counter to the first and second preloading springs (21, 39) in axial positions at which the interlocking elements (28) of the first latching mechanism (24) at least partially engage into the piston (4) and block movement of the piston (4).

6. The device of claim 1, wherein the interlocking elements (28, 29) of the first and second latching mechanisms (24, 25) each respectively engage into a radial inner groove (45, 46) of the piston (4) in a latching manner.

7. The device of claim 1, wherein the first preloading spring (21) is arranged between an annular collar (35) of the armature rod (20) and the housing-affixed component.

8. The device of claim 7, wherein the annular collar (35) is a stop of the actuating element (37) positioned proximate the electromagnet (19) on the armature rod (20).

9. The device of claim 1, wherein the first and second latching mechanisms (24, 25) are each configured as a ball stop and comprise balls as the interlocking elements (28, 29).

10. The device of claim 9, wherein: the ball stops (24, 25) are centrally arranged within the piston (4); the balls (28, 29) of both ball stops (24, 25) are accommodated in an axially fixed manner in the housing-affixed component (30); the housing-affixed component (30) is configured as a sleeve; and the balls (28, 29) of the ball stops (24, 25) are radially displaceable with respect to the sleeve (30) and are selectively engageable with the piston (4) by way of rolling at the respective actuating contour (22, 23).

11. The device of claim 1, wherein: the interlocking elements are configured as spring arms; first ends of the spring arms are fixed on the housing side; and second ends of the spring arms are each swivelable relative to a respective first end by way of the actuating contours and, as a result, are selectively engageable with the piston in a form-locking manner.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Multiple exemplary embodiments of the invention are explained in greater detail with reference to the drawings, without being limited thereto.

(2) Wherein:

(3) FIG. 1 shows a highly schematicized partial representation of a parking lock system of an automatic transmission; and

(4) FIG. 2a to FIG. 2e show an enlarged view of a device for actuating a parking lock of the parking lock system according to FIG. 1 in various operating conditions.

DETAILED DESCRIPTION

(5) Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

(6) A schematic part longitudinal cutaway view of a parking lock system 1 known from practical experience, including a device 2 for actuating a parking lock 3, is represented in FIG. 1. The device 2 includes an actuator, which includes a piston 4, which can be acted upon by fluid. The piston 4 is actuatable in the opening direction or in the direction of a disengaged condition of the parking lock 3, depending on the particular applied fluid pressure, counter to a spring unit 5 acting in the closing direction or an engaged condition of the parking lock 3. For this purpose, the piston 4 is arranged, displaceably in the axial direction, in a cylinder 6 of the actuator. Additionally, the piston 4 is connected to a deflecting mechanism 8 via a piston rod 7. In the present case, the deflecting mechanism 8 includes a rotary disk 9, which is designed to be rotatable in the area of a pin 10. The spring unit 5 is designed as a compression spring in the present case and is connected at one end to the rotary disk 9. At the other end, the spring unit is supported in the area of a housing 11.

(7) Moreover, the rotary disk 9 is operatively connected to a parking interlock rod 14, which is coupled to a parking interlock cone 15. The parking interlock cone 15 cooperates with a parking pawl 16. The parking pawl 16 is engageable, via an axial movement of the piston 4, with a parking interlock gear 17, which is rotationally fixed to an output shaft of a vehicle drive train, in order to rotationally fix the output shaft. If the parking pawl 16 is guided out of the engagement with the parking interlock gear 17 via an axial movement of the piston 4 in the opposite direction, the parking lock 3 is disengaged and the output shaft can rotate.

(8) A device 203 represented in FIG. 2a through FIG. 2e for actuating the parking lock 3 has the same functionality as the device 2 in each case. Therefore, the same reference numbers are used in the description and in the drawing for structurally and functionally identical components of the devices 2 and 203.

(9) With respect to the device 203 for actuating the parking lock 3, the spring unit 5 is arranged between an end face 12 of the piston 4 and an inner side 13 of the cylinder 6 facing the end face 12 of the piston 4. The spring unit 5 is designed as a compression spring in each case, in order to be able to engage the parking lock 3 in the non-pressurized condition of the piston 4.

(10) The device 203 includes a piston 4, which is longitudinally movably arranged in a cylinder 6. The piston 4 can be acted upon by hydraulic fluid in the area of an end face 12A starting from a hydraulic port 18 and counter to the spring force of a spring unit 5. At an appropriate pressure, a piston rod 7 is transferable out of the position shown in FIG. 2a, which corresponds to the engaged condition of the parking lock 3, into the position shown in FIG. 2e, in which the parking lock 3 is disengaged.

(11) Two actuating elements 37 and 38 of a locking unit are axially displaceably mounted on an armature rod 20 of an interlocking unit, between two stops 35 and 36 of the armature rod 20. A further preloading spring 39 is mounted between the two actuating elements 37 and 38.

(12) The actuating element 37 proximate or close to the magnet includes an actuating contour 22 facing an electromagnet 19 of the interlocking unit, which is associated with a latching mechanism 24 of the locking unit designed as a ball stop. With the aid of the ball stop 24, the piston 4 is mechanically fixable in the disengaged condition of the parking lock 3. Additionally, the actuating element 38 remote from the magnet includes an actuating contour 23 facing away from the electromagnet 19, which is associated with a further latching mechanism 25 designed as a ball stop. With the aid of the further ball stop 25, the piston 4 is mechanically fixable in the engaged condition of the parking lock 3.

(13) Both ball stops 24 and 25 are centrally arranged within the piston 4. Interlocking elements 28 and 29 of the ball stops 24 and 25, which are designed as balls, are accommodated in an axially fixed manner in a component 30 designed as a housing-affixed sleeve, wherein axial movements of the balls 28, 29 are largely prevented by the sleeve 30. The balls 28 and 29 are each radially displaceable with respect to the sleeve 30 and can be brought into engagement or out of the engagement with the piston 4 by way of rolling at the particular associated actuating contour 22 and 23, respectively.

(14) The components of the device 203 are coordinated with each other with respect to their geometry and with respect to the forces acting upon each of the components in such a way that, in the engaged condition of the parking lock 3, the actuating contour 23 remote from the magnet or the actuating element 38 remote from the magnet blocks a radial movement of the balls 29 of the associated ball stop 25 in the non-energized condition of the electromagnet 19 and releases the radial movement in the energized condition of the electromagnet 19. Moreover, the coordination is such that, in the disengaged condition of the parking lock 3, the actuating contour 22 of the actuating element 37 close to the magnet blocks a radial movement of the balls 28 of the associated ball stop 24 in the energized condition of the electromagnet 19 and releases the radial movement in the non-energized condition of the electromagnet 19.

(15) The piston 4, the armature rod 20, and the two actuating elements 37 and 38 have the axial positions shown in FIG. 2a in the non-energized condition of the electromagnet 19 as well as in the engaged condition of the parking lock 3. Thereupon, the balls 29 of the ball stop 25 are pushed radially outward by the actuating element 38 remote from the magnet, through the sleeve 30, into a radial inner groove 46 of the piston. Thereupon, the piston 4 is locked with respect to the cylinder 6 and is axially fixed. This means, the piston 4 cannot be displaced either by the spring unit 5 in the direction of the engaged condition of the parking lock 3 or by the hydraulic pressure applied via the hydraulic port 18 in the direction of the disengaged operating condition of the parking lock 3. In this operating condition of the device 203, the actuating element 38 remote from the magnet rests against the stop 36, while the actuating element 37 close to the magnet is pressed against the stop 35 by the further preloading spring 39.

(16) In the presence of a demand to disengage the parking lock 3, the electromagnet 19 is energized. Due to the magnetic force of the electromagnet 19, which is then applied at the armature rod 20, the armature rod 20 is pulled, counter to the spring force of the preloading spring 21, in the direction of the electromagnet 19 and is transferred into the axial position shown in FIG. 2b. Since the actuating element 37 close to the magnet rests against the radially non-displaceable balls 28 of the ball stop 24, the stop 35 lifts off of the actuating element 37. Simultaneously, the actuating element 38 is axially displaced, together with the armature rod 20, in the direction of the electromagnet 19 by the stop 36. As a result, the further preloading spring 39 is compressed and preloaded between the two actuating elements 37 and 38.

(17) In the axial position of the actuating element 38 remote from the magnet shown in FIG. 2b, the balls 29 are displaceable radially inward with respect to the sleeve 30 and, therefore, brought out of the engagement with the radial inner groove 46 of the piston 4. This means, in the energized condition of the electromagnet 19 and in the engaged condition of the parking lock 3, the ball stop 25 the piston 4 releases an axial actuating movement of the piston 4 directed away from the electromagnet 19.

(18) The piston 4 carries out an actuating movement of this type when the hydraulic pressure applied via the hydraulic port 18 or the actuating force resulting therefrom and active at the piston 4 in the direction of the disengaged condition of the parking lock 3 is greater than the spring force of the spring unit 5. If this is the case, the piston 4 is transferred against the spring force of the spring unit 5 out of the axial position shown in FIG. 2b into the axial position shown in FIG. 2c, wherein, as a result, the disengagement of the parking lock 3 is started.

(19) If the piston 4 is further displaced in the axial direction, the axial distance between the electromagnet 19 and the piston 4, as well as the piston rod 7 connected thereto, increases until the piston 4 has the axial position shown in FIG. 2d. The latter-described axial position of the piston 4 corresponds to the disengaged operating condition of the parking lock 3. In this position of the piston 4, a further radial inner groove 45 of the piston 4 is in overlap with the balls 28 of the ball stop 24. In this position of the piston 4, the balls 28 are guidable outwardly in the radial direction through the sleeve 30 into the radial inner groove 46 and, therefore, are engaged with the piston 4. This condition is shown in FIG. 2e.

(20) In the process, the balls 28 are pushed radially outward by the preloaded further preloading spring 39, which displaces the actuating element 37 close to the magnet in the direction of the stop 35, and the piston 4 as well as the piston rod 7 are locked or latched to the desired extent with the aid of the ball stop 24 close to the magnet. As a result, an undesirable engagement of the parking lock 3 is prevented in the energized condition of the electromagnet 19.

(21) If there is an appropriate demand to engage the parking lock 3, the energization of the electromagnet 19 is switched off. As a result, the armature rod 20, together with the actuating elements 37 and 38, are axially displaced by the preloading spring 21 away from the electromagnet 19. The stiffness constants of the preloading springs 21 and 39 are matched to each other in such a way that a base point 26 of the actuating contour 22 of the actuating element 37 close to the magnet is then arranged underneath the balls 28 of the ball stop 24 and the balls 28 are guidable radially inward out of the engagement with the radial inner groove 45.

(22) Therefore, the piston 4 is released in the disengaged operating condition of the parking lock 3 and in the non-energized condition of the electromagnet 19. The parking lock 3 is transferable into the engaged operating condition by the spring unit 5 when an appropriate hydraulic pressure is present in the area of the hydraulic port 18. Thereafter, the ball stop 25 latches the piston 4 to the extent represented in FIG. 2a, in order to avoid an undesirable disengagement of the parking lock 3.

(23) The radial inner grooves 45 and 46 are designed including lateral surfaces 32A, 33A and 32B, 33B, which are pitched with respect to the radial direction. Via the beveled lateral surfaces 32A, 33A and 32B, 33B of the radial inner grooves 45, 46, an undesirable misalignment or jamming of the ball stops 24 and 25 is prevented in a simple way.

(24) Moreover, it is also possible to design the latching mechanisms of the locking unit not including the interlocking elements designed as balls, but rather including interlocking elements designed as spring arms. The spring arms are swivelably operatively connected to the cylinder 6 and preferably include a hook-like end. Interlocking elements of this type are known, for example, from EP 1 960 701 B1 and are swivelable radially outward with the aid of the actuating contours 22 and 23, in order to prevent an actuating movement of the piston 4 or, in the swiveled-in condition, to release the piston 4.

(25) Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.

REFERENCE CHARACTERS

(26) 1 parking lock system 2 device 3 parking lock 4 piston 5 spring unit 6 cylinder 7 piston rod 8 deflecting mechanism 9 rotary disk 10 pin 11 housing 12 end face of the piston 12A further end face of the piston 13 inner side of the cylinder 14 parking interlock rod 15 parking interlock cone 16 parking pawl 17 parking interlock gear 18 hydraulic port 19 electromagnet 20 armature rod 21 preloading spring 22 actuating contour 23 actuating contour 24 latching mechanism, ball stop 25 latching mechanism, ball stop 26 base point of the actuating contour 22 27 base point of the actuating contour 23 28 interlocking element, ball of the ball stop 24 29 interlocking element, ball of the ball stop 25 30 sleeve 32A to 33B lateral surfaces of the radial inner grooves 45 and 46 34 sensor 35 annular collar, stop 36 stop 37 actuating element 38 actuating element 39 further preloading spring 45 radial inner groove 46 radial inner groove