U.S. patent application number 14/402233 was filed with the patent office on 2015-05-28 for control valve of a camshaft adjuster.
The applicant listed for this patent is Schaeffler Technologies GmbH & Co. KG. Invention is credited to Alexander Backer, Alexander Fichtner, Jens Hoppe, Markus Kinscher, Christoph Ross.
Application Number | 20150144211 14/402233 |
Document ID | / |
Family ID | 49547147 |
Filed Date | 2015-05-28 |
United States Patent
Application |
20150144211 |
Kind Code |
A1 |
Kinscher; Markus ; et
al. |
May 28, 2015 |
CONTROL VALVE OF A CAMSHAFT ADJUSTER
Abstract
A control valve (1) of a camshaft adjuster is provided having a
multi-part housing (2) that is formed as a screw
Inventors: |
Kinscher; Markus; (Lauf a.d.
Pegnitz, DE) ; Hoppe; Jens; (Erlangen, DE) ;
Backer; Alexander; (Grafenberg, DE) ; Ross;
Christoph; (Stegaurach, DE) ; Fichtner;
Alexander; (Memmelsdorf, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schaeffler Technologies GmbH & Co. KG |
Herzogenaurach |
|
DE |
|
|
Family ID: |
49547147 |
Appl. No.: |
14/402233 |
Filed: |
March 8, 2013 |
PCT Filed: |
March 8, 2013 |
PCT NO: |
PCT/EP2013/054761 |
371 Date: |
November 19, 2014 |
Current U.S.
Class: |
137/596 |
Current CPC
Class: |
F01L 5/14 20130101; Y10T
137/87169 20150401; F01L 1/3442 20130101; F01L 1/344 20130101 |
Class at
Publication: |
137/596 |
International
Class: |
F01L 1/344 20060101
F01L001/344; F01L 5/14 20060101 F01L005/14 |
Foreign Application Data
Date |
Code |
Application Number |
May 25, 2012 |
DE |
10 2012 208 786.9 |
Mar 8, 2013 |
DE |
10 2013 203 951.4 |
Claims
1. A control valve of a camshaft adjuster, that carries a flow of
hydraulic medium for controlling the camshaft adjuster, the control
valve comprises: a supply connection (P), several work connections
(A, B), and a tank connection (T), a housing formed as a screw with
a cylindrical hollow space in which a control piston is guided so
that it is movable in an axial direction, the housing formed as a
screw has a multiple-part construction including a threaded body
and a sleeve, and the threaded body is connected to the sleeve
which is arranged peripheral to the threaded body.
2. The control valve according to claim 1, wherein the threaded
body has a positive locking element that is held in a complementary
receptacle of the sleeve, and a connection between the sleeve and
the threaded body is formed by positive locking.
3. The control valve according to claim 2, wherein the
complementary receptacle is arranged inside the sleeve.
4. The control valve according to claim 2, wherein the
complementary receptacle is arranged outside the sleeve.
5. The control valve according to claim 1, wherein the sleeve
includes the cylindrical hollow space having a guide surface that
guides the control piston so that it is movable in the axial
direction.
6. The control valve according to claim 1, wherein the sleeve is
constructed as a deep-drawn part or extruded part.
7. The control valve according to claim 1, wherein the threaded
body is constructed as a formed part.
8. The control valve according to claim 1, wherein the threaded
body has a central passage opening.
9. The control valve according to claim 1, wherein the threaded
body has an external thread that is engageable with an inner thread
of a camshaft.
10. The control valve according to claim 1, wherein the sleeve has
a screw head on an end side of the sleeve that is formed as flange.
Description
FIELD OF THE INVENTION
[0001] The invention relates to a control valve of a camshaft
adjuster.
BACKGROUND
[0002] Camshaft adjusters are used in internal combustion engines
to vary the control times of combustion chamber valves, in order to
be able to vary the phase relationship between a crankshaft and a
camshaft in a defined angular range between a maximum advanced
position and a maximum retarded position. The adaptation of the
control times to the current load and engine speed reduces fuel
consumption and emissions. For this purpose, camshaft adjusters are
integrated into a drive train by which a torque is transferred from
the crankshaft to the camshaft. This drive train can be formed, for
example, as a belt, chain, or gearwheel drive.
[0003] For a hydraulic camshaft adjuster, the driven element and
the drive element form one or more pairs of pressure chambers that
act against each other and can be loaded with hydraulic medium. The
drive element and the driven element are arranged coaxially. By
filling and emptying individual pressure chambers, a relative
movement is generated between the drive element and the driven
element. A spring with a rotating action between the drive element
and the driven element forces the drive element opposite the driven
element in a preferred direction. This preferred direction can be
in the same direction or opposite direction relative to the
rotational direction.
[0004] One construction of the hydraulic camshaft adjuster is the
vane cell adjuster. The vane cell adjuster has a stator, a rotor,
and a drive wheel with an outer toothed section. The rotor is
formed as a driven element usually so that it can be locked in
rotation with the camshaft. The drive element includes the stator
and the drive wheel. The stator and the drive wheel are locked in
rotation with each other or alternatively formed integrally with
each other. The rotor is arranged coaxial to the stator and within
the stator. With their radially extending vanes, the rotor and the
stator form oil chambers that act opposite each other and can be
loaded by oil pressure and allow a relative rotation between the
stator and the rotor. The vanes are formed either integrally with
the rotor or the stator or arranged as "inserted vanes" in grooves
of the rotor or stator provided for this purpose. Furthermore, the
vane cell adjusters have various sealing covers. The stator and the
sealing covers are secured with each other by means of several
screw connections.
[0005] A different construction of the hydraulic camshaft adjuster
is the axial piston adjuster. Here, a displacement element is
shifted axially by means of oil pressure and this displacement
element generates a relative rotation between a drive element and a
driven element by means of helical toothed sections.
[0006] The control valves of the hydraulic camshaft adjusters
control the hydraulic medium flow between the camshaft adjuster and
the oil pump or the oil reservoir (tank).
[0007] The control valve has a hollow cylindrical housing and a
rotationally symmetric control piston. The control piston is within
the housing of the control valve. The control piston can move in
the axial direction and is guided by the housing. Thus, the control
piston can be positioned in an arbitrary axial position relative to
the housing. The positioning is realized by an electromagnet that
contacts an end of the control piston with its actuation pin and
can shift the control piston. A spring ensures contact between the
control piston and the actuation pin. Through the axial positioning
of the control piston, the different connections of the control
valve are connected to each other hydraulically or separated from
each other and can communicate with each other or not. For guiding
the hydraulic medium between the connections, the control piston
and housing are provided with openings, e.g., grooves and/or holes.
The control piston has control edges that control the flow together
with the edges of the openings of the housing. The control edges
themselves are the edges of the respective openings, e.g., grooves,
of the control piston. For controlling the flow, the edges of the
openings of the housing and the control edges are positioned
relative to each other, so that an opening of the housing lies
opposite an opening of the control piston as much as possible and
forms a variable flow surface for the hydraulic medium by means of
being able to position the control piston in the axial
direction.
[0008] A control valve formed as a central valve is arranged
coaxial to the axis of symmetry or rotation of the camshaft
adjuster or the camshaft. In addition, the central valve is placed
within the camshaft adjuster, i.e., central valve and camshaft
adjuster are arranged one on top of the other in the radial
direction. Optionally, the camshaft can be arranged between the
camshaft adjuster and the central valve. The housing of the central
valve can be formed as a central screw, wherein the camshaft
adjuster is locked in rotation with the camshaft. The electromagnet
is arranged as a central magnet aligned as much as possible with
the central valve and arranged usually fixed on the frame,
especially on the cylinder head.
[0009] Alternatively, a control valve with an electromagnet
arranged rigidly on the valve can be arranged on an arbitrary
position in the hydraulic medium gallery, outside of the camshaft
adjuster and the camshaft, and can control the hydraulic medium
flow.
SUMMARY
[0010] The object of the invention is to provide a control valve of
a camshaft adjuster that permits a more economical production.
[0011] This object is met by a control valve of a camshaft
adjuster, wherein the control valve for controlling the camshaft
adjuster carries a flow of hydraulic medium and the control valve
has a supply connection, multiple work connections, and a tank
connection, wherein the control valve has a housing formed as a
screw with a cylindrical hollow space in which a control piston is
guided so that it can move in the axial direction, wherein the
housing formed as a screw is formed in multiple parts and has a
threaded body and a sleeve, wherein the threaded body is connected
to the sleeve arranged peripheral to the threaded body.
[0012] The housing has several openings and a control piston that
can move in the axial direction in the cylindrical hollow space of
the housing, wherein a control edge of the control piston can be
positioned in the axial direction relative to an opening of the
housing for controlling the hydraulic medium flow between the
supply connection, the work connections, and the tank connection,
in order to change the flow path for the hydraulic medium flow
between the connections through the opening.
[0013] The control valve is preferably formed as a central valve
and thus the housing as a central screw, by which the camshaft
adjuster is locked in rotation with the camshaft.
[0014] Through the invention it is advantageously achieved that
different threaded bodies can be combined with a sleeve or
different sleeves with a threaded body. Another advantage is that
the production and heat treatment can be individually adapted to
both components. In addition, different materials can be used for
the threaded body and for the sleeve.
[0015] Different threaded bodies can vary in length, thread pitch,
and thread type and can be adapted to an individual receptacle,
e.g., of the camshaft, provided for this purpose. The threaded body
is advantageously formed as a threaded bar and has a thread
section, an elongation section, and a positive locking section. The
thread section is provided for anchoring, e.g., to a camshaft. The
elongation section is formed for providing the elasticity necessary
for the thread connection. The positive locking section is formed
for the positive locking attachment to the sleeve. As an
alternative to the positive locking section, a non-positive locking
section or a material locking section could also be provided for
the non-positive or material locking and rotationally fixed
attachment to the sleeve.
[0016] Different sleeves can vary in length, diameter, and
production quality and can be adapted to an individual receptacle,
e.g., the hub of the camshaft adjuster, provided for this
purpose.
[0017] The sleeve can have, on one of its ends, an attachment body
for a mounting tool, preferably for mounting the camshaft adjuster
with the camshaft. The attachment body is advantageously formed as
a hexagon analogous to a hexagonal screw head. Alternative screw
body shapes can be formed instead of the hexagon screw head.
[0018] In one advantageous construction of the invention, the
threaded body has a positive locking element that is held in a
complementary receptacle of the sleeve, wherein, by means of the
positive locking, a connection is formed between the sleeve and the
threaded body. The positive locking fixes the sleeve relative to
the threaded body at least in the axial direction. The
complementary receptacle can be arranged preferably in the base of
the sleeve or on an inner periphery or outer periphery of the
sleeve.
[0019] Preferably the positive locking element also has surfaces on
a circumferential face that match surfaces of the complementary
receptacle of the sleeve such that a torque can be transferred
between both components. In this way, as mentioned above, an
attachment body is formed for an installation tool of the
sleeve.
[0020] Alternatively, the positive locking between the sleeve and
threaded body cannot transmit sufficient torque for fastening the
camshaft adjuster to the camshaft. For example, the sleeve and
threaded body are fixed axially and/or radially to each other, but
the positive locking allows rotation between the sleeve and
threaded body. In this case, the threaded body has an attachment
body for an installation tool. The attachment body is
advantageously formed as a hexagon analogous to a hexagonal screw.
Alternative screw head shapes can be formed instead of the
hexagonal screw head. This rotational capability can be formed
completely without resistance, that is, with play, or can be formed
without play at least up to a certain torque that, however, is not
sufficient for fastening of the camshaft adjuster on the
camshaft.
[0021] In a detailed construction of the invention, the
complementary receptacle is arranged inside the sleeve. Preferably
the complementary receptacle can be arranged in the interior of the
sleeve on a surface turned toward the interior of the sleeve on an
inner periphery or the base. Similarly, the sleeve can have a pin
that has the complementary receptacle on its inner periphery.
[0022] In an alternative detailed construction of the invention,
the complementary receptacle is arranged outside the sleeve.
Preferably, the complementary receptacle can be arranged in the
inside of the sleeve on the surface turned toward the outside of
the sleeve on an outer periphery or the base. Similarly, the sleeve
can have a pin that has the complementary receptacle for the
positive locking element of the threaded body on its outer
periphery.
[0023] In one preferred construction of the invention, the sleeve
has the cylindrical hollow space with a guide surface that guides
the control piston so it can move in the axial direction. The guide
surface can be formed here by an inner circumferential surface of
the sleeve itself or by an inner circumferential surface of an
intermediate sleeve.
[0024] In another construction of the invention, the sleeve is
formed as a deep drawn part or an extruded part. Preferably, these
production methods can improve the economical production.
[0025] In a preferred construction of the invention, the threaded
body is constructed as a formed part. Preferably, this production
method can improve the economical production.
[0026] In addition to forming, a material-cutting method,
preferably turning, can be used to form the final shape of the
threaded body. Alternatively, the threaded body can be produced
only by a material-cutting method, preferably turning.
[0027] In another construction, the threaded body has a central
passage opening. Preferably, this passage opening can be formed as
a supply connection, work connection, or tank connection of the
control valve.
[0028] In a very preferred construction of the invention, the
threaded body has an external thread that can be brought into
engagement with an internal thread of a camshaft. Alternatively,
the threaded body has an internal thread that can be brought into
engagement with an external thread of a camshaft. Preferably, the
thread, either internal thread or external, of the threaded body
can be adapted to the thread of the camshaft or different threads
of the threaded body can be adapted to different camshafts, without
having to change the shape or production technique of the sleeve,
preferably with the control piston arranged therein.
[0029] In one especially preferred construction of the invention,
the sleeve has a screw head on an end side of the sleeve that is
formed as a flange. Preferably, both a stop for the camshaft
adjuster and also an attachment body for an installation tool are
formed on the flange and thus a space-saving arrangement is made.
Alternatively, the screw head could be formed on an end side of the
threaded body, wherein the sleeve nevertheless has a stop,
preferably a flange, for the camshaft adjuster.
[0030] Due to the construction according to the invention for the
control valve, for one, a more economical production of the control
valve is possible and, second, many different configurations of
different sleeves with different threaded bodies can be made,
primarily, for installation, which enables high flexibility with
respect to a wide spectrum of applications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Embodiments of the invention are shown in the figures.
[0032] Shown are:
[0033] FIG. 1 a control valve formed as a central valve, and
[0034] FIG. 2 a multiple-part housing according to the invention of
a control valve formed as a central valve.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0035] FIG. 1 shows a control valve 1 formed as a central
valve.
[0036] The control valve 1 has a multiple-part housing 2, a plastic
sleeve 15, a guide sleeve 3, a control valve 4, two compression
springs 18 and 20, a valve seat plate 21, a ball 19, a control
piston 4, a spring support plate 33, and optionally a spacer 22.
All of the components named above are arranged coaxial to each
other and to a common axis of rotation 34 that is also the axis of
rotation 34 of a camshaft adjuster or a camshaft.
[0037] The multiple-part housing 2 that is formed as a screw is
provided for the rotationally locked attachment of the camshaft
adjuster to the camshaft. The multiple-part housing 2 is formed of
a sleeve 6 and a threaded body 5. The plastic sleeve 15 is held by
an inner circumferential surface of the sleeve 6. The plastic
sleeve 15 has channels and openings to guide hydraulic medium from
a supply connection P of the control valve 1 to the work
connections A and B. The work connections A and B are arranged at
different, angle-offset positions as radial holes 24 and 25 of the
sleeve 6. The supply connection P is formed by a passage opening 10
in the threaded body 5. The passage opening 10 is formed as a hole
coaxial to the rotational axis 34 and passes completely through the
threaded body 5. The tank connection is located on the end side 13
of the control valve 1 opposite the supply connection P.
[0038] Force is applied to the control piston 4 by the compression
spring 18 and this control piston is pressed against the securing
ring 17. The securing ring 17 secures the axial position of the
plastic sleeve 15 and the control piston 4 inside the sleeve 6. The
compression spring 18 is supported, on one side, on the control
piston 4 and, on the other side, on the spring support plate 33.
The spring support plate 33 is connected rigidly to the plastic
sleeve 15, as are also the guide sleeve 16 and the valve seat plate
21. The ball 19 is pressed by the compression spring 20 against the
valve seat plate 21. These three components form a non-return valve
that permits a flow of hydraulic medium from the supply connection
P into the inside of the control valve 1, but prevents a return
flow.
[0039] The control piston 4 is guided by means of its outer
circumference by a guide surface 9 of the guide sleeve 16. The
housing 2 or the sleeve 6 has a hole 23 that is closed by the
spacer 22. On one hand, the spacer 22 positions the plastic sleeve
15 so that the hydraulic medium can reach from the holes 24 and 25
to the control piston 4. On the other hand, the spacer 22 can also
have, in addition to its passage opening arranged coaxial to the
rotational axis 34, several radial holes that can optionally lead
hydraulic medium from the hole 23 to the control piston 4 and thus
can provide the hole 23 as an additional supply connection, work
connection, or tank connection.
[0040] The control of the hydraulic medium flow between the
connections P, T, A, and B is known by those skilled in the art.
The control of the hydraulic medium to the work connections A and
B, which lead to the work chambers of the camshaft adjuster, is
also known from the prior art and generates the relative adjustment
between the camshaft and crankshaft. The control piston 4 is
shifted according to the prior art by an actuation pin of an
electromagnet, in particular, a central magnet, in its axial
position, so that the hydraulic medium can be distributed from the
supply connection P to the work connections A and B.
[0041] The sleeve 6 has a flange 14 on the end side 13 on which the
tank connection T is arranged and a perforated base 35 on the end
side 30 opposite the end side 13. The inner circumferential surface
36 of the perforated base 35 has a circular shape and is arranged
coaxial to the rotational axis 24. This inner circumferential
surface 36 is part of the complementary receptacle 8 for the
positive locking element 7, wherein this inner circumferential
surface 36 contacts an outer circumferential surface 37 of the
positive locking section 27 of the threaded body 5 and fixes the
threaded body 5 radial to the rotational axis 34. Radial play
between the inner circumferential surface 36 and the outer
circumferential surface 37 can be provided or not.
[0042] In the axial direction along the rotational axis 34 and in
the direction of the end side 13, the inner circumferential surface
36 contacts a circular inner surface 40 that is formed as an axial
stop for the threaded body 5 for the axial positioning of the
threaded body 5 relative to the sleeve 6. The circular inner
surface 40 is part of the complementary receptacle 8 for the
positive locking element 7 and contacts a circular outer surface 41
of the positive locking section 27 of the threaded body 5.
[0043] In addition, the complementary receptacle 8 of the sleeve 6
has another inner circumferential surface 38 that has a larger
diameter than the inner circumferential surface 36. In the axial
direction along the rotational axis 34 and in the direction of the
end side 13, the inner circumferential surface 38 contacts the
circular inner surface 40. This inner circumferential surface 38
contacts an outer circumferential surface 39 of the positive
locking section 27 of the threaded body 5 and fixes the threaded
body 5 in the radial direction relative to the rotational axis 34
with the sleeve 6. Radial play between the inner circumferential
surface 38 and the outer circumferential surface 39 can be provided
or not.
[0044] At a minimum, the positive locking can have a rotationally
fixed construction either between the inner circumferential surface
38 and the outer circumferential surface 39 or between the inner
circumferential surface 36 and the outer circumferential surface
37.
[0045] Alternatively, the inner circumferential surface 38 and the
outer circumferential surface 39 and/or the inner circumferential
surface 36 and the outer circumferential surface 37 can have a
cylindrical shape and each can be provided with or without radial
play. If there is no radial play in at least one surface pair, this
non-positive locking fit, preferably an interference fit, can form
the rotationally locked connection. If radial play is provided in
both surface pairs, the rotationally fixed connection can be formed
by fusion, adhesion, or welding.
[0046] The threaded body 5 is divided into three sections the
positive locking section 27, the elongation section 26, and the
threaded section 31. The positive locking section 27 has the
cylindrical outer circumferential surface 37, the circular
ring-shaped outer surface 41, and the cylindrical outer
circumferential surface 39. In the direction of the rotational axis
34, the elongation section 26 that has a smaller cross section than
the positive locking section 27 or the threaded section 31 contacts
the cylindrical outer circumferential surface 39 of the positive
locking section 27. The elongation section 26 is constructed in its
length and its cross section such that the desired pretensioning
force can be realized. Furthermore, in the axial direction along
the rotational axis 34, the threaded section 31 that has an
external thread for engaging with an internal thread of a camshaft
connects with the elongation section 26.
[0047] The threaded body 6 is constructed as a formed part. The
positive locking section 27 with its surfaces for the complementary
receptacle 8, the elongation section 26, and the threaded section
31 are formed by material extrusion. The external thread of the
threaded section 31 is rolled. The passage opening 10 can be either
drilled or formed by an extrusion method. Cutting methods, e.g.,
such as turning or grinding, can also be used for forming desired
tolerance areas.
[0048] Starting from the base 35 passed through by the threaded
body 5 and then at the complementary receptacle 8, the sleeve 6 has
the cylindrical hollow space 3 in which the previously mentioned
components are arranged. On the end side 13 of the sleeve 6 there
is a flange 14 that is formed as a radially projecting collar. The
flange 14 has an engagement body 32 with a screw head 12 and also a
contact surface 28 for contacting a camshaft adjuster. The
engagement body 32 has several surfaces that form the screw head 12
on the outer circumference of the flange 14. The arrangement of the
surfaces corresponds to an external hexagon. The contact surface 28
is formed as a circular ring-shaped surface and oriented toward the
other end side 30.
[0049] The sleeve 6 is constructed as a formed part, preferably as
a deep drawn or extruded part. The structure of the engagement body
32 of the flange 14 formed as a screw head 12, as well as the
cylindrical hollow space 3 and the complementary receptacle 8, can
be preferably formed by this method. The hole in the base 35 and
also the radial holes 23, 24, 25 can be formed by a punching
process. Cutting methods, e.g., turning or grinding, can also be
used for forming desired tolerance areas.
[0050] Through the rotationally locked connection between the
positive locking section 27 of the threaded body 5 and the
complementary receptacle 8 of the sleeve 6, a torque is
transmitted, starting from an installation tool that acts on the
engagement body 32 constructed as screw head 12 to the threaded
section 31 of the threaded body 5. In this way, the control valve 1
constructed as a central valve can be used with its multiple-part
housing 2 formed as a screw for the rotationally locked connection
of a camshaft adjuster to a camshaft.
[0051] FIG. 2 shows a multiple-part housing 2 according to the
invention in a control valve 1 formed as a central valve. The
configuration is similar to the housing 2 from FIG. 1, so only the
differences will be discussed below.
[0052] The engagement body 32 is constructed by the positive
locking section 27 of the threaded body 5. The screw head 12 of the
engagement body 32 is here formed as an internal hexagon. The
flange 14 has a cylindrical external lateral surface and
functionally has only the contact surface 28 that is provided for
contacting a camshaft adjuster. In addition, the flange 14 is
arranged at a distance from the end surface 13. The elongation
section 26 and the threaded section 31 have an external diameter
that is uniform as much as possible. The arrangement and the
construction of the connections (feed connection, work connection,
tank connection) is here disregarded in favor of clearly explaining
the invention. The surface pairing of the inner circumferential
surface 38 and the outer circumferential surface 39 can be
constructed as shown. The inner circumferential surface 38 is
constructed as an inner hexagon and the outer circumferential
surface 39 is constructed cylindrically. A small amount of play or
even no play can be provided in this surface pairing.
[0053] The inner circumferential surface 38 formed as an inner
hexagon can alternatively be paired to an outer circumferential
surface 39 formed as an external hexagon, wherein a rotationally
locked connection can be formed between the sleeve 6 and the
threaded body 5.
[0054] In contrast to the construction of the control valve 1
according to FIG. 1, according to the construction according to
FIG. 2 first the multiple-part housing 2 with a camshaft adjuster
and a camshaft is installed, whereupon the assembly contacts the
component arranged in the cylindrical hollow space. The guide
surface 9 of the cylindrical hollow space 3 can be contacted
directly by a control piston 4.
TABLE-US-00001 List of Reference Numbers 1) Control valve 2)
Housing 3) Cylindrical hollow space 4) Control piston 5) Threaded
body 6) Sleeve 7) Positive locking element 8) Complementary
receptacle 9) Guide surface 10) Passage opening 11) Outer thread
12) Screw head 13) End side 14) Flange 15) Plastic sleeve 16) Guide
sleeve 17) Securing ring 18) Compression spring 19) Ball 20)
Compression spring 21) Valve seat plate 22) Spacer 23) Hole 24)
Hole 25) Hole 26) Elongation section 27) Positive locking section
28) Contact surface 29) Outer circumferential surface 30) End side
31) Threaded section 32) Contact body 33) Spring support plate 34)
Axis of rotation 35) Base 36) Inner circumferential surface 37)
Outer circumferential surface 38) Inner circumferential surface 39)
Outer circumferential surface 40) Inner surface 41) Outer surface
A) Work connection B) Work connection P) Supply connection T) Tank
connection
* * * * *