diff --git a/trytond/trytond/model/fields/date.py b/trytond/trytond/model/fields/date.py
index b934f6d66b..d2e9737915 100644
--- a/trytond/trytond/model/fields/date.py
+++ b/trytond/trytond/model/fields/date.py
@@ -46,6 +46,11 @@ class Date(Field):
             expression = AtTimeZone(expression, timezone)
         return super(Date, self).sql_cast(expression)
 
+    def __set__(self, inst, value):
+        if isinstance(value, str):
+            value = datetime.date.fromisoformat(value)
+        super().__set__(inst, value)
+
 
 class FormatMixin(Field):
 
@@ -86,6 +91,11 @@ class Timestamp(FormatMixin, Field):
             return SQLite_DateTime(expression)
         return super().sql_cast(expression)
 
+    def __set__(self, inst, value):
+        if isinstance(value, str):
+            value = datetime.datetime.fromisoformat(value)
+        super().__set__(inst, value)
+
 
 class DateTime(Timestamp):
     '''
@@ -148,6 +158,11 @@ class Time(FormatMixin, Field):
             return SQLite_Time(expression)
         return super(Time, self).sql_cast(expression)
 
+    def __set__(self, inst, value):
+        if isinstance(value, str):
+            value = datetime.time.fromisoformat(value)
+        super().__set__(inst, value)
+
 
 class TimeDelta(Field):
     _type = 'timedelta'
@@ -172,14 +187,20 @@ class TimeDelta(Field):
         if isinstance(value, (int, float)):
             value = datetime.timedelta(seconds=value)
         elif isinstance(value, str):
-            if not value.find(':'):
-                raise ValueError(
-                    "TimeDelta requires a string '%H:%M:%S.%f' or '%H:%M'")
             hours, minutes, seconds = (value.split(":") + ['00'])[:3]
             value = datetime.timedelta(
                 hours=int(hours), minutes=int(minutes), seconds=float(seconds))
         return super().sql_format(value)
 
+    def __set__(self, inst, value):
+        if isinstance(value, (int, float)):
+            value = datetime.timedelta(seconds=value)
+        elif isinstance(value, str):
+            hours, minutes, seconds = (value.split(":") + ['00'])[:3]
+            value = datetime.timedelta(
+                hours=int(hours), minutes=int(minutes), seconds=float(seconds))
+        super().__set__(inst, value)
+
     @classmethod
     def get(cls, ids, model, name, values=None):
         result = {}
diff --git a/trytond/trytond/tests/test_field_date.py b/trytond/trytond/tests/test_field_date.py
index 618bd9b918..242d194f2e 100644
--- a/trytond/trytond/tests/test_field_date.py
+++ b/trytond/trytond/tests/test_field_date.py
@@ -27,6 +27,17 @@ class FieldDateTestCase(TestCase):
         super().setUpClass()
         activate_module('tests')
 
+    @with_transaction()
+    def test_set_string(self):
+        "Test set string"
+        pool = Pool()
+        Model = pool.get('test.date')
+
+        record = Model()
+        record.date = str(today)
+
+        self.assertEqual(record.date, today)
+
     @with_transaction()
     def test_create(self):
         "Test create date"
diff --git a/trytond/trytond/tests/test_field_datetime.py b/trytond/trytond/tests/test_field_datetime.py
index 8c0abdb971..db704bfb4c 100644
--- a/trytond/trytond/tests/test_field_datetime.py
+++ b/trytond/trytond/tests/test_field_datetime.py
@@ -24,6 +24,17 @@ class FieldDateTimeTestCase(TestCase):
         super().setUpClass()
         activate_module('tests')
 
+    @with_transaction()
+    def test_set_string(self):
+        "Test set string"
+        pool = Pool()
+        Model = pool.get('test.datetime')
+
+        record = Model()
+        record.datetime = str(today)
+
+        self.assertEqual(record.datetime, today)
+
     @with_transaction()
     def test_create(self):
         "Test create datetime"
diff --git a/trytond/trytond/tests/test_field_time.py b/trytond/trytond/tests/test_field_time.py
index 5f088109c7..bddc90d950 100644
--- a/trytond/trytond/tests/test_field_time.py
+++ b/trytond/trytond/tests/test_field_time.py
@@ -24,6 +24,17 @@ class FieldTimeTestCase(TestCase):
         super().setUpClass()
         activate_module('tests')
 
+    @with_transaction()
+    def test_set_string(self):
+        "Test set string"
+        pool = Pool()
+        Model = pool.get('test.time')
+
+        record = Model()
+        record.time = str(evening)
+
+        self.assertEqual(record.time, evening)
+
     @with_transaction()
     def test_create(self):
         "Test create time"
diff --git a/trytond/trytond/tests/test_field_timedelta.py b/trytond/trytond/tests/test_field_timedelta.py
index 209b67642d..9273b8e42a 100644
--- a/trytond/trytond/tests/test_field_timedelta.py
+++ b/trytond/trytond/tests/test_field_timedelta.py
@@ -21,6 +21,30 @@ class FieldTimeDeltaTestCase(TestCase):
         super().setUpClass()
         activate_module('tests')
 
+    @with_transaction()
+    def test_set_string(self):
+        "Test set string"
+        pool = Pool()
+        Model = pool.get('test.timedelta')
+
+        record = Model()
+        record.timedelta = '1:20:30.5'
+
+        self.assertEqual(
+            record.timedelta,
+            datetime.timedelta(hours=1, minutes=20, seconds=30.5))
+
+    @with_transaction()
+    def test_set_integer(self):
+        "Test set integer"
+        pool = Pool()
+        Model = pool.get('test.timedelta')
+
+        record = Model()
+        record.timedelta = 42
+
+        self.assertEqual(record.timedelta, datetime.timedelta(seconds=42))
+
     @with_transaction()
     def test_create(self):
         "Test create timedelta"